Estrogen receptor modulators

ABSTRACT

Isoxazole estrogen receptor agonist and antagonist compounds having unexpected and surprising activity in modulating estrogen receptor activity are described. In addition, methods and compositions for treating or preventing estrogen receptor-mediated disorders are disclosed. The compounds, methods, and compositions of the invention have utility in preventing or treating estrogen receptor-mediated disorders such as osteoporosis, breast and endometrial cancers, atherosclerosis, and Alzheimer&#39;s disease.

1 CROSS REFERENCE TO RELATED U.S. PATENT APPLICATIONS

The present application claims priority under 35 U.S.C. § 119(e) from co-pending provisional U.S. patent application Ser. No. 60/095,773, which is incorporated herein by reference in its entirety and for all purposes.

2 BACKGROUND OF THE INVENTION

2.1 Field of the Invention

The present invention relates to compounds that have biological activity with respect to estrogen receptors and to the use of such compounds to treat diseases and disorders related to estrogen receptor activity. More particularly, the present invention provides selective estrogen receptor modulators (“SERMs”). The present invention therefore relates to the fields of medicine, medicinal chemistry, biochemistry, and endocrinology.

2.2 Background

Estrogen is a hormone critical to normal human development and function. Although estrogen is the predominant “sex hormone” in women, in whom estrogen controls the development of female sex characteristics and the development and function of the reproductive system (Berkow, Beers et al 1997), it is also found in men (Gustafsson 1998). Women produce estrogen primarily in the ovaries; however, estrogen affects a variety of physiological functions in women including body temperature regulation, maintenance of the vaginal lining, and preservation of bone density (Jordan 1998). In addition, estrogen provides additional effects that are related to its ability to modulate production of cholesterol in the liver, as demonstrated by the reduced occurrence of atherocsclerosis in women compared to men due in part to the reduction of low-density lipoprotein (“LDL”) (Jordan 1998). Estrogen has also been implicated in delaying and/or reducing the severity of Alzheimer's Disease (Jordan 1998).

Failure to produce estrogen has profound physiological consequences in females. Failure to produce estrogen resulting from incomplete or absent ovary development (Turner's Syndrome) causes deficiencies in the skin, bone (e.g., severe osteoporosis), and other organs severely affecting the life of the afflicted individual (Dodge 1995). In normal women, estrogen production falls sharply upon the onset of menopause, usually at about 50 years of age. The effects of the loss of estrogen production include increased atherosclerotic deposits (leading to greatly increase incidence of heart disease), decreased bone density (osteoporosis), and fluctuations in body temperature among others (Jordan 1998). Often, the effects of reduced estrogen production are addressed by hormone replacement therapy (Dodge 1995; Berkow, Beers et al. 1997; Jordan 1998).

However, estrogen also has undesirable effects. In menopausal women, supplementation of estrogen is associated with alleviation of the above-described unwanted effects. But, administration of estrogen is also associated with increased risks for breast and endometrial cancer as well as blood clots (Jordan 1998). The increased risk of endometrial cancer can be addressed by the administration of progesterone (or its synthetic analog progestin) to reinitiate menstruation and thereby shed potentially malignant cells, but many older women find this undesirable (Jordan 1998). Breast cancer, however, is by far the greater risk of estrogen replacement therapy, affecting one woman in every 15 between the ages of 60 and 79 (Jordan 1998).

Thus, for a long time the treatment options for the serious health problems caused by a failure to produce estrogen were limited and entailed severe risks. However, the discovery that some agents acted as estrogen agonists in some tissues (e.g., bone) and as an antagonists in other tissues (e.g., breast) provided hope that more effective treatments for estrogen loss could be found (Gradishar and Jordan 1997; Gustafsson 1998; Jordan 1998; MacGregor and Jordan 1998). The best known of these so-called Selective Estrogen Receptor Modulators (“SERMs”), tamoxifen, has been demonstrated to have therapeutic utility in treating and preventing breast cancer and lowering LDL concentrations; yet, without significant reduction bone density (Jordan 1998; MacGregor and Jordan 1998). However, tamoxifen has been associated with endometrial cancer and venous blood clots (Jordan 1998; MacGregor and Jordan 1998). In addition, tumor resistance to tamoxifen can occur (MacGregor and Jordan 1998).

Tamoxifen has been followed recently by newer SERMs, in particular raloxifene, that promise to provide many of tamoxifen's benefits with fewer risks (Howell, Downey et al. 1996; Gradishar and Jordan 1997; Gustafsson 1998; Jordan 1998; Purdie 1999; Sato, Grese et al. 1999). These newer SERMs, including idoxifene (Nuttall, Bradbeer et al. 1998), CP-336,156 (Ke, Paralkar et al. 1998), GW5638 (Willson, Norris et al. 1997), LY353581 (Sato, Turner et al. 1998) are part of the second- and third generation of partial estrogen agonists/antagonists. In addition, a new generation of pure antiestrogens such as RU 58,688 (Van de Velde, Nique et al. 1994) have been reported. A large number of additional partial and pure estrogen agonist/antagonist compounds and treatment modalities have reported recently (Bryant and Dodge 1995; Bryant and Dodge 1995; Cullinan 1995; Dodge 1995; Grese 1995; Labrie and Merand 1995; Labrie and Merand 1995; Thompson 1995; Audia and Neubauer 1996; Black, Bryant et al. 1996; Thompson 1996; Cullinan 1997; Wilson 1997; Miller, Collini et al. 1999; Palkowitz 1999; Wilson 1999).

However, no one drug candidate has emerged to fill the needs of women who require the benefits of estrogen replacement to live productive lives and/or treatments for estrogen-dependent cancers. The efforts to develop better partial and pure estrogen agonists and antagonists has been aided by several recent developments, including the discovery that human estrogen receptor has at least two isoforms (“ERα” and “ERβ”) and the crystal structure of ERα that have permitted high-resolution structure-acitivty relationship studies (Sadler, Cho et al. 1998). Recently, a study of the application of combinatorial synthetic methods combined with three-dimensional structure-activity analysis to develop SERMs having optimal therapeutic profiles was reported (Fink, Mortensen et al. 1999). That study examined several heterocyclic motifs (imidazoles, thiazoles, pyrazoles, oxazoles, and isoxazoles) and identified certain pyrazole motifs as being well suited for combinatorial development of SERMs. The relative binding effectiveness of the pyrazoles viz. the other motifs was based on its ability to carry four substituents in addition to polarity consideration (see p. 215). In particular, the study referred the capacity of the pyrazole motif to carry four substituents explained the binding effectiveness pyrazoles compared to the poor binding results found for the oxazole, thiazole, and isoxazole motifs.

However, despite these recent advances no drug candidate has emerged to fill the needs of women who require the benefits of estrogen replacement to live productive lives and/or treatments for estrogen-dependent cancers. The present invention addresses these and other needs.

3 SUMMARY OF THE INVENTION

The present invention provides isoxazole estrogen receptor agonist and antagonist compounds in addition to methods and compositions for treating or preventing estrogen receptor-mediated disorders. The compounds described herein have been found to have unexpected and surprising activity in modulating estrogen receptor activity. Thus, the compounds of the present invention have utility in preventing or treating estrogen receptor-mediated disorders such as osteoporosis, breast and endometrial cancers, atherosclerosis, and Alzheimer's disease.

In a first aspect, the present invention provides compounds having the structure shown below:

and its pharmaceutically acceptable salts. X₁ and X₂ are selected independently from the group consisting of nitrogen and oxygen such that if one of X₁ and X₂ is nitrogen, then the other of X₁ and X₂ is oxygen to form thereby an isoxazole ring structure. R₁ and R₃ are selected independently from the group consisting of optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl. R₂ is selected from the group consisting of hydrogen, halo, cyano, nitro, thio, amino, carboxyl, formyl, and optionally substituted loweralkyl, loweralkylcarbonyloxy, arylcarbonyloxy, heteroarylcarbonyloxy, cycloalkylcarbonyloxy, cycloheteroalkylcarbonyloxy, aralkycarbonyloxy, heteroaralkylcarbonyloxy, (cycloalkyl)alkylcarbonyloxy, (cycloheteroalkyl)alkylcarbonyloxy, loweralkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, cycloalkylcarbonyl, cycloheteroalkylcarbonyl, aralkycarbonyl, heteroaralkylcarbonyl, (cycloalkyl)alkylcarbonyl, (cycloheteroalkyl)alkylcarbonyl, loweralkylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, cycloalkylaminocarbonyl, (cycloalkyl)alkylaminocarbonyl, cycloheteroalkylaminocarbonyl, (cycloheteroalkyl)alkylaminocarbonyl, loweralkylcarbonylamino, arylcarbonylamino, heteroarylcarbonylamino, cycloalkylcarbonylamino, cycloheteroalkylcarbonylamino, aralkylcarbonylamino, heteroaralkylcarbonylamino, (cycloalkyl)alkylcarbonylamino, (cycloheteroalkyl)alkylcarbonylamino, loweralkylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino, loweralkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, cycloalkylsulfonyl, cycloheteroalkylsulfonyl, aralkylsulfonyl, heteroaralkylsulfonyl, (cycloalkyl)alkylsulfonyl, (cycloheteroalkyl)alkylsulfonyl, loweralkylsulfinyl, arylsulfinyl, heteroarylsulfinyl, cycloalkylsulfinyl, cycloheteroalkylsulfinyl, aralkylsulfinyl, heteroaralkylsulfinyl, (cycloalkyl)alkylsulfinyl, (cycloheteroalkyl)alkylsulfinyl, loweralkyloxy, aryloxy, heteroaryloxy, cycloalkyloxy, cycloheteroalkyloxy, aralkyloxy, heteroaralkyloxy, (cycloalkyl)alkyloxy, and (cycloheteroalkyl)alkyloxy, loweralkylthio, arylthio, heteroarylthio, cycloalkylthio, cycloheteroalkylthio, aralkylthio, heteroaralkylthio, (cycloalkyl)alkylthio, (cycloheteroalkyl)alkylthio, loweralkylthiocarbonyl, arylthiocarbonyl, heteroarylthiocarbonyl, cycloalkylthiocarbonyl, cycloheteroalkylthiocarbonyl, aralkythiocarbonyloxythiocarbonyl, heteroaralkylthiocarbonyl, (cycloalkyl)alkylthiocarbonyl, (cycloheteroalkyl)alkylthiocarbonyl, heteroarylcarbonylthio, cycloalkylcarbonylthio, cycloheteroalkylcarbonylthio, aralkycarbonylthiooxycarbonylthio, heteroaralkylcarbonylthio, (cycloalkyl)alkylcarbonylthio, (cycloheteroalkyl)alkylcarbonylthio, loweralkyloxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, cycloalkyloxycarbonyl, cycloheteroalkyloxycarbonyl, aralkyoxycarbonyl, heteroaralkyloxycarbonyl, (cycloalkyl)alkyloxycarbonyl, (cycloheteroalkyl)alkyloxycarbonyl, iminoloweralkyl, iminocycloalkyl, iminocycloheteroalkyl, iminoaralkyl, iminoheteroaralkyl, (cycloalkyl)iminoalkyl, (cycloheteroalkyl)iminoalkyl, (cycloiminoalkyl)alkyl, (cycloiminoheteroalkyl)alkyl, oximinoloweralkyl, oximinocycloalkyl, oximinocycloheteroalkyl, oximinoaralkyl, oximinoheteroaralkyl, (cycloalkyl)oximinoalkyl, (cyclooximinoalkyl)alkyl, (cyclooximinoheteroalkyl)alkyl, and (cycloheteroalkyl)oximinoalkyl.

In one more specific embodiment of the invention, R₂ is selected from the group consisting of hydrogen, halo, and optionally substituted loweralkyl, haloloweralkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, aryloxyalkyl, arylthioalkyl, arylcarbonyl, heteroarylcarbonyl, loweralkylcarbonyl, aminocarbonyl, arylaminocarbonyl, loweralkylaminocarbonyl, aralkylaminocarbonyl, (heterocycloloweralkyl)alkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, (cycloloweralkyl)aminocarbonyl, formyl, amino, loweralkylamino, and alkenyl. More particular embodiments are those for which R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl. Examples of R₂ substituents within this embodiment having useful properties include, but are not limited to, 4-(2-piperidin-1-ylethyloxy)phenylcarbonyl, 4-hydroxyphenylcarbonyl, (phenylmethyl)aminocarbonyl, 3-(2-oxopyrrolidin-1-yl)propylaminocarbonyl, di-n-butylaminocarbonyl, (4-hydroxyphenylmethyl)aminocarbonyl, (pyridin-3-ylmethyl)aminocarbonyl, (pyridin-2-ylmethyl)aminocarbonyl, dimethylaminocarbonyl, ethylaminocarbonyl, 4-(2-morpholinoethyloxy)phenylcarbonyl, 4-(3-dimethylaminopropyloxy)phenylcarbonyl, cyclopropylaminocarbonyl, cyclobutylaminocarbonyl, 4-(2-dimethylaminoethyloxy)phenylcarbonyl, 4-[2-(benzylmethylamino)ethyloxy]phenylcarbonyl, 4-(1-methylpiperidin-3-ylmethyloxy)phenylcarbonyl, 4-[2-(1-methylpyrrolidin-2-yl)ethyloxy]phenylcarbonyl, 4-[2-(4-methylpiperazin-1-yl)ethyloxy]phenylcarbonyl, 4-(1-methylpiperidin-4-ylmethyloxy)phenylcarbonyl, 2-chlorophenylcarbonyl, 3-chlorophenylcarbonyl, 4-chlorophenylcarbonyl, 3-nitrophenylcarbonyl, 4-nitrophenylcarbonyl, 3,4-dichlorophenylcarbonyl, 4-n-butylphenylcarbonyl, 3-hydroxyphenylcarbonyl, 2-hydroxyphenylcarbonyl, 4-methoxyphenylcarbonyl, 3-(2-piperidin-1-ylethyloxy)phenylcarbonyl, 3-(2-diethylaminoethyloxy)phenylcarbonyl, 3-[2-(pyrrolidin-1-yl)ethyloxy]phenylcarbonyl, 3-(1-methylpiperidin-3-ylmethyloxy)phenylcarbonyl, and 3-(2-dimethylaminoethyloxy)phenylcarbonyl.

In other embodiments of the invention, R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl, R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl, at least one of R₁ and R₃ is selected independently from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, at least one of R₁ and R₃ is substituted with at least one hydroxyl or thio group, and at least one of R₁ and R₃ is substituted optionally with a substituent selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, and heteroaralkylaminocarbonyl. Examples of specific useful groups for R₁ and R₃ include without limitation 2-methyl-4-hydroxyphenyl, 2-aminocarbonyl-4-hydroxyphenyl, 4-methylsulfonylaminophenyl, 3-aminocarbonyl-4-hydroxyphenyl, 3-aminocarbonyl-4-methoxyphenyl, 3-chloro-4-hydroxyphenyl, 4-methylcarbonyloxyphenyl, 3-n-hexyl-4-hydroxyphenyl, 4-n-propylcarbonyloxyphenyl, 3-ethyl-4-hydroxyphenyl, 2-methylsulfinyl-4-hydroxyphenyl, 2-ethyl-4-hydroxyphenyl, 2-carboxy-4-hydroxyphenyl, 3-fluoro-4-hydroxyphenyl, 2-iodo-4-hydroxyphenyl, 2-n-butyl-4-hydroxyphenyl, 2-trifluoromethoxyphenyl, and 4-fluorophenyl.

In another aspect, the present invention provides estrogen receptor-modulating compounds having the following structure:

and their pharmaceutically acceptable salts. X₃ and X₄ are selected independently from the group consisting of nitrogen and oxygen such that if one of X₃ and X₄ is nitrogen, then the other of X₃ and X₄ is oxygen to form thereby an isoxazole ring structure. X₅ is —(X₁₀)_(n)—, wherein n is an integer between 1 and 3 and X₁₀, for each value of n, is selected independently from the group consisting of oxygen, —SO_(x)— where x is and integer between 0 and 2, nitrogen, nitrogen substituted with optionally substituted loweralkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, arylcarbonyl, alkylcarbonyl, aralkylcarbonyl, heteroarylcarbonyl, heteroaralkylcarbonyl, and methylene or methine, each optionally substituted from the group consisting of halo, cyano, nitro, thio, amino, carboxyl, formyl, and optionally substituted loweralkyl, loweralkylcarbonyloxy, arylcarbonyloxy, heteroarylcarbonyloxy, cycloalkylcarbonyloxy, cycloheteroalkylcarbonyloxy, aralkycarbonyloxy, heteroaralkylcarbonyloxy, (cycloalkyl)alkylcarbonyloxy, (cycloheteroalkyl)alkylcarbonyloxy, loweralkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, cycloalkylcarbonyl, cycloheteroalkylcarbonyl, aralkycarbonyl, heteroaralkylcarbonyl, (cycloalkyl)alkylcarbonyl, (cycloheteroalkyl)alkylcarbonyl, loweralkylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, loweralkylcarbonylamino, arylcarbonylamino, heteroarylcarbonylamino, cycloalkylcarbonylamino, cycloheteroalkylcarbonylamino, aralkylcarbonylamino, heteroaralkylcarbonylamino, (cycloalkyl)alkylcarbonylamino, (cycloheteroalkyl)alkylcarbonylamino, loweralkylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino, loweralkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, cycloalkylsulfonyl, cycloheteroalkylsulfonyl, aralkylsulfonyl, heteroaralkylsulfonyl, (cycloalkyl)alkylsulfonyl, (cycloheteroalkyl)alkylsulfonyl, loweralkylsulfinyl, arylsulfinyl, heteroarylsulfinyl, cycloalkylsulfinyl, cycloheteroalkylsulfinyl, aralkylsulfinyl, heteroaralkylsulfinyl, (cycloalkyl)alkylsulfinyl, (cycloheteroalkyl)alkylsulfinyl, loweralkyloxy, aryloxy, heteroaryloxy, cycloalkyloxy, cycloheteroalkyloxy, aralkyloxy, heteroaralkyloxy, (cycloalkyl)alkyloxy, and (cycloheteroalkyl)alkyloxy, loweralkylthio, arylthio, heteroarylthio, cycloalkylthio, cycloheteroalkylthio, aralkylthio, heteroaralkylthio, (cycloalkyl)alkylthio, (cycloheteroalkyl)alkylthio, loweralkylthiocarbonyl, arylthiocarbonyl, heteroarylthiocarbonyl, cycloalkylthiocarbonyl, cycloheteroalkylthiocarbonyl, aralkythiocarbonyloxlthiocarbonyl, heteroaralkylthiocarbonyl, (cycloalkyl)alkylthiocarbonyl, (cycloheteroalkyl)alkylthiocarbonyl, heteroarylcarbonylthio, cycloalkylcarbonylthio, cycloheteroalkylcarbonylthio, aralkycarbonylthiooxycarbonylthio, heteroaralkylcarbonylthio, (cycloalkyl)alkylcarbonylthio, (cycloheteroalkyl)alkylcarbonylthio, loweralkyloxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, cycloalkyloxycarbonyl, cycloheteroalkyloxycarbonyl, aralkyoxycarbonyloxloxycarbonyl, heteroaralkyloxycarbonyl, (cycloalkyl)alkyloxycarbonyl, (cycloheteroalkyl)alkyloxycarbonyl, iminoloweralkyl, iminocycloalkyl, iminocycloheteroalkyl, iminoaralkyl, iminoheteroaralkyl, (cycloalkyl)iminoalkyl, and (cycloheteroalkyl)iminoalkyl. X₆-X₉ are selected independently from the group consisting of oxygen, sulfur, sulfinyl, nitrogen, and optionally substituted methine, and R₄ is selected from the group consisting of optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl.

In some more specific embodiments of this aspect of the invention, n is 1 and X₁₀ is selected from the group consisting of nitrogen, optionally substituted nitrogen, and optionally substituted methylene or methine, and R₄ is selected from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. Still more specific embodiments include those for which n and X₁₀ have the values just defined and R₄ is optionally substituted aryl or aralkyl. In still more specific embodiments, which n, X₁₀ and R₄ have the values just defined R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Yet more specific embodiments are those for which n and X₁₀ have the values just defined wherein R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, and R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Other embodiments are those for which n and X₁₀ have the values just defined R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety, and R₄ is further substituted optionally with a moiety selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, cyano, nitro, amino, loweralkylamino, and heteroaralkylaminocarbonyl.

Other embodiments of the present invention include those structures for which n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine. In some embodiments, X₁₀ and n have the values just described and R₄ is selected from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. Still more specific embodiments include those for which n and X₁₀ have the values just defined and R₄ is optionally substituted aryl or aralkyl. In still more specific embodiments, which n and X₁₀ have the values just defined, R₄ is optionally substituted aryl or aralkyl, and R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Yet more specific embodiments are those for which n and X₁₀ have the values just defined wherein R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, and R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Other embodiments are those for which n and X₁₀ have the values just defined wherein R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety, and R₄ is further substituted optionally with a moiety selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, cyano, nitro, amino, loweralkylamino, and heteroaralkylaminocarbonyl.

Other embodiments of the present invention include compounds for which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine. More particular embodiments are those for which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine, and at least one of X₆-X₉ is methine substituted with a moiety selected from the group consisting of loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, and heteroarylcarbonyl. Still more particular embodiments having the structural pattern just described include those in which X₇ is methine substituted with hydroxy or loweralkyloxy.

In yet another aspect, the present invention provides the present invention provides methods for treating or preventing an estrogen receptor-mediated disorder in a human or animal subject in which an amount of an estrogen receptor-modulating compound of the invention that is effective to modulate estrogen receptor activity in the subject. Other embodiments provided methods for treating a cell or a estrogen receptor-mediated disorder in a human or animal subject, comprising administering to the cell or to the human or animal subject an amount of a compound or composition of the invention effective to modulate estrogen receptor activity in the cell or subject. Representative estrogen receptor-mediated disorders include, for example, osteoporosis, atheroschlerosis, estrogen-mediated cancers (e.g., breast and endometrial cancer), and Alzheimer's disease.

These and other aspects and advantages will become apparent when the Description below is read in conjunction with the accompanying Examples.

4 DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

4.1 Definitions

4.1.1 Estrogen Receptor

“Estrogen Receptor” as defined herein refers to any protein in the nuclear receptor gene family that binds estrogen, including, but not limited to, any isoforms or deletion mutations having the characteristics just described. More particularly, the present invention relates to estrogen receptor(s) for human and non-human mammals (e.g., animals of veterinary interest such as horses, cows, sheep, and pigs, as well as household pets such as cats and dogs). Human estrogen receptors included in the present invention include the α- and β-isoforms (referred to herein as “ERα” and “ERβ”) in addition to any additional isoforms as recognized by those of skill in the biochemistry arts.

4.1.2 Estrogen Receptor Modulator

“Estrogen Receptor Modulator” refer herein to a compound that can act as an estrogen receptor agonist or antagonist of estrogen receptor having an IC₅₀ or EC₅₀ with respect to ERα and/or ERβ of no more than about 10 μM as determined using the ERα and/or ERβ transactivation assay described hereinbelow (Section 5.2.2.3). More typically, estrogen receptor modulators of the invention have IC₅₀ or EC₅₀ values (as agonists or antagonists) of not more than about 5 μM. Representative compounds of the present invention have been discovered to exhibit agonist or antagonist activity viz. estrogen receptor. Compounds of the present invention preferably exhibit an antagonist or agonist IC₅₀ or EC₅₀ with respect to ERα and/or ERβ of no more than about 5 μM, more preferably, no more than about 500 nM, even more preferably not more than about 1 nM, and most preferably, not more than about 500 pM, as measured in the ERα and/or ERβ transactivation assays. “IC₅₀” is that concentration of inhibitor which reduces the activity of a target (e.g., ERα or ERβ) to half-maximal level. “EC₅₀” is that concentration of modulator that produces half-maximal effect.

4.1.3 Selective Estrogen Receptor Modulator

A “Selective Estrogen Receptor Modulator” (or “SERM”) is a compound that exhibits activity as an agonist or antagonist of an estrogen receptor (e.g., ERα or ERβ) in a tissue-dependent manner. Thus, as will be apparent to those of skill in the biochemistry and endocrinology arts, compounds of the invention that function as SERMs can act as estrogen receptor agonists in some tissues (e.g., bone, brain, and/or heart) and as antagonists in other tissue types, such as the breast and/or uterine lining.

4.1.4 Optionally Substituted

“Optionally substituted” refers to the replacement of hydrogen with a monovalent or divalent radical. Suitable substitution groups include, for example, hydroxyl, nitro, amino, imino, cyano, halo, thio, thioamido, amidino, oxo, oxamidino, methoxamidino, imidino, guanidino, sulfonamido, carboxyl, formyl, loweralkyl, haloloweralkyl, loweralkoxy, haloloweralkoxy, loweralkoxyalkyl, alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, heteroarylcarbonyl, heteroaralkylcarbonyl, alkylthio, aminoalkyl, cyanoalkyl, and the like. The substitution group can itself be substituted. The group substituted onto the substitution group can be, for example, carboxyl, halo; nitro, amino, cyano, hydroxyl, loweralkyl, loweralkoxy, aminocarbonyl, —SR, thioamido, —SO₃H, —SO₂R or cycloalkyl, where R is typically hydrogen, hydroxyl or loweralkyl. When the substituted substituent includes a straight chain group, the substitution can occur either within the chain (e.g., 2-hydroxypropyl, 2-aminobutyl, and the like) or at the chain terminus (e.g. 2-hydroxyethyl, 3-cyanopropyl, and the like). Substituted substitutents can be straight chain, branched or cyclic arrangements of covalently bonded carbon or heteroatoms.

4.1.5 Loweralkyl and Related Terms

“Loweralkyl” as used herein refers to branched or straight chain alkyl groups comprising one to ten carbon atoms that independently are unsubstituted or substituted, e.g., with one or more halogen, hydroxyl or other groups. Examples of loweralkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, n-hexyl, neopentyl, trifluoromethyl, pentafluoroethyl, and the like.

“Alkylenyl” refers to a divalent straight chain or branched chain saturated aliphatic radical having from 1 to 20 carbon atoms. Typical alkylenyl groups employed in compounds of the present invention are loweralkylenyl groups that have from 1 to about 6 carbon atoms in their backbone. “Alkenyl” refers herein to straight chain, branched, or cyclic radicals having one or more double bonds and from 2 to 20 carbon atoms. “Alkynyl” refers herein to straight chain, branched, or cyclic radicals having one or more triple bonds and from 2 to 20 carbon atoms.

The term “haloloweralkyl” refers to a loweralkyl radical substituted with one or more halogen atoms.

“Loweralkoxy” as used herein refers to RO— wherein R is loweralkyl. Representative examples of loweralkoxy groups include methoxy, ethoxy, t-butoxy, trifluoromethoxy and the like.

“Loweralkythio” as used herein refers to RS— wherein R is loweralkyl.

The term “alkoxyalkyl” refers to the group -alk₁-O-alk₂ where alk₁ is alkylenyl or alkenyl, and alk₂ is alkyl or alkenyl. The term “loweralkoxyalkyl” refers to an alkoxyalkyl where alk₁ is loweralkylenyl or loweralkenyl, and alk₂ is loweralkyl or loweralkenyl. The term “aryloxyalkyl” refers to the group -alkylenyl-O-aryl. The term “aralkoxyalkyl” refers to the group -alkylenyl-O-aralkyl, where aralkyl is a loweraralkyl.

“Cycloalkyl” refers to a mono- or polycyclic, loweralkyl substituent. Typical cycloalkyl substituents have from 3 to 8 backbone (i.e., ring) atoms in which each backbone atom is optionally substituted carbon. When used in context with cycloalkyl substituents, the term “polycyclic” refers herein to fused, non-fused cyclic carbon structures and spirocycles. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, bornyl, norbornyl, and the like.

The term “cycloheteroalkyl” refers herein to cycloalkyl substituents that have from 1 to 5, and more typically from 1 to 4 heteroatoms (i.e., non-carbon atoms such as nitrogen, sulfur, and oxygen) in the ring structure, with the balance of atoms in the ring being optionally substituted carbon. Representative heterocycloalkyl moieties include, for example, morpholino, piperazinyl, piperidinyl, pyrrolidinyl, methylpryolidinyl, pyrrolidinone-yl, and the like.

The terms “(cycloalkyl)alkyl” and “(cycloheteroalkyl)alkyl” refer to alkyl chains substituted with cycloalkyl and cycloheteroalkyl groups respectively.

The term “haloalkoxy” refers to an alkoxy radical substituted with one or more halogen atoms. The term “haloloweralkoxy” refers to a loweralkoxy radical substituted with one or more halogen atoms.

4.1.6 Halo

“Halo” refers herein to a halogen radical, such as fluorine, chlorine, bromine, or iodine.

4.1.7 Aryl and Related Terms

“Aryl” refers to monocyclic and polycyclic aromatic groups, or fused ring systems having at least one aromatic ring, having from 3 to 14 backbone carbon atoms. Examples of aryl groups include without limitation phenyl, naphthyl, dihydronaphtyl, tetrahydronaphthyl, and the like.

“Aralkyl” refers to an alkyl group substituted with an aryl group. Typically, aralkyl groups employed in compounds of the present invention have from 1 to 6 carbon atoms incorporated within the alkyl portion of the aralkyl group. Suitable aralkyl groups employed in compounds of the present invention include, for example, benzyl, picolyl, and the like.

4.1.8 Heteroaryl and Related Terms

The term “heteroaryl” refers herein to aryl groups having from one to four heteroatoms as ring atoms in an aromatic ring with the remainder of the ring atoms being aromatic or non-aromatic carbon atoms. When used in connection with aryl substituents, the term “polycyclic” refers herein to fused and non-fused cyclic structures in which at least one cyclic structure is aromatic, such as, for example, benzodioxozolo, naphthyl, and the like. Exemplary heteroaryl moieties employed as substituents in compounds of the present invention include pyridyl, pyrimidinyl, thiazolyl, indolyl, imidazolyl, oxadiazolyl, tetrazolyl, pyrazinyl, triazolyl, thiophenyl, furanyl, quinolinyl, purinyl, benzothiazolyl, benzopyridyl, and benzimidazolyl, and the like.

4.1.9 Amino and Related Terms

“Amino” refers herein to the group —NH₂. The term “loweralkylamino” refers herein to the group —NRR′ where R and R′ are each independently selected from hydrogen or loweralkyl. The term “arylamino” refers herein to the group —NRR′ where R is aryl and R′ is hydrogen, loweralkyl, aryl, or aralkyl. The term “aralkylamino” refers herein to the group —NRR′ where R is aralkyl and R′ is hydrogen, loweralkyl, aryl, or aralkyl. The terms “heteroarylamino” and heteroaralkylamino” are defined by analogy to arylamino and aralkylamino.

The term “aminocarbonyl” refers herein to the group —C(O)—NH₂. The terms “loweralkylaminocarbonyl”, arylaminocarbonyl”, “aralkylaminocarbonyl”, “heteroarylaminocarbonyl”, and “heteroaralkylaminocarbonyl” refer to —C(O)NRR′ where R and R′ independently are hydrogen and optionally substituted loweralkyl, aryl, aralkyl, heteroaryl, and heteroaralkyl respectively by analogy to the corresponding terms above.

4.1.10 Thio, Sulfonyl, Sulfinyl and Related Terms

The term “thio” refers to —SH. The terms “loweralkylthio”, “arylthio”, “heteroarylthio”, “cycloalkylthio”, “cycloheteroalkylthio”, “aralkylthio”, “heteroaralkylthio”, “(cycloalkyl)alkylthio”, and “(cycloheteroalkyl)alkylthio” refer to —SR, where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

The term “sulfonyl” refers herein to the group —SO₂—. The terms “loweralkylsulfonyl”, “arylsulfonyl”, “heteroarylsulfonyl”, “cycloalkylsulfonyl”, “cycloheteroalkylsulfonyl”, “aralkylsulfonyl”, “heteroaralkylsulfonyl”, “(cycloalkyl)alkylsulfonyl”, and “(cycloheteroalkyl)alkylsulfonyl” refer to —SO₂R where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

The term “sulfinyl” refers herein to the group —SO—. The terms “loweralkylsulfinyl”, “arylsulfinyl”, “heteroarylsulfinyl”, “cycloalkylsulfinyl”, “cycloheteroalkylsulfinyl”, “aralkylsulfinyl”, “heteroaralkylsulfinyl”, “(cycloalkyl)alkylsulfinyl, and “(cycloheteroalkyl)alkylsulfinyl” refer to —SOR where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

4.1.11 Formyl, Carboxyl, Carbonyl, Thiocarbonyl, and Related Terms

“Formyl” refers to —C(O)H.

“Carboxyl” refers to —C(O)OH.

“Carbonyl” refers to the divalent group —C(O)—. The terms “loweralkylcarbonyl”, “arylcarbonyl”, “heteroarylcarbonyl”, “cycloalkylcarbonyl”, “cycloheteroalkylcarbonyl”, “aralkycarbonyl”, “heteroaralkylcarbonyl”, “(cycloalkyl)alkylcarbonyl”, and “(cycloheteroalkyl)alkylcarbonyl” refer to —C(O)R, where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

“Thiocarbonyl” refers to the group —C(S)—. The terms “loweralkylthiocarbonyl”, “arylthiocarbonyl”, “heteroarylthiocarbonyl”, “cycloalkylthiocarbonyl”, “cycloheteroalkylthiocarbonyl”, “aralkythiocarbonyloxlthiocarbonyl”, “heteroaralkylthiocarbonyl”, “(cycloalkyl)alkylthiocarbonyl”, and “(cycloheteroalkyl)alkylthiocarbonyl” refer to —C(S)R, where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

“Carbonyloxy” refers generally to the group —C(O)—O—. The terms “loweralkylcarbonyloxy”, “arylcarbonyloxy”, “heteroarylcarbonyloxy”, “cycloalkylcarbonyloxy”, “cycloheteroalkylcarbonyloxy”, “aralkycarbonyloxy”, “heteroaralkylcarbonyloxy”, “(cycloalkyl)alkylcarbonyloxy”, “(cycloheteroalkyl)alkylcarbonyloxy” refer to —C(O)OR, where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

“Oxycarbonyl” refers to the group —O—C(O)—. The terms “loweralkyloxycarbonyl”, “aryloxycarbonyl”, “heteroaryloxycarbonyl”, “cycloalkyloxycarbonyl”, “cycloheteroalkyloxycarbonyl”, “aralkyoxycarbonyloxloxycarbonyl”, “heteroaralkyloxycarbonyl”, “(cycloalkyl)alkyloxycarbonyl”, “(cycloheteroalkyl)alkyloxycarbonyl” refer to —O—C(O)R, where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

“Carbonylamino” refers to the group —NH—C(O)—. The terms “loweralkylcarbonylamino”, “arylcarbonylamino”, “heteroarylcarbonylamino”, “cycloalkylcarbonylamino”, “cycloheteroalkylcarbonylamino”, “aralkylcarbonylamino”, “heteroaralkylcarbonylamino”, “(cycloalkyl)alkylcarbonylamino”, and “(cycloheteroalkyl)alkylcarbonylamino” refer to —NH—C(O)R, where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, or (cycloheteroalkyl)alkyl respectively. In addition, the present invention includes N-substituted carbonylamino (—NR′C(O)R), where R′ is optionally substituted loweralkyl, aryl, heteroaryl, aralkyl, or heteroaralkyl and R retains the previous defintion.

“Carbonylthio” refers to the group —C(O)—S—. The terms “loweralkylcarbonylthio”, “arylcarbonylthio”, “heteroarylcarbonylthio”, “cycloalkylcarbonylthio”, “cycloheteroalkylcarbonylthio”, “aralkycarbonylthio”, “heteroaralkylcarbonylthio”, “(cycloalkyl)alkylcarbonylthio”, “(cycloheteroalkyl)alkylcarbonylthio” refer to —C(O)SR, where R is optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl respectively.

4.1.12 Guanidino or Guanidyl

As used herein, the term “guanidino” or “guanidyl” refers to moieties derived from guanidine, H₂N—C(═NH)—NH₂. Such moieties include those bonded at the nitrogen atom carrying the formal double bond (the “2”-position of the guanidine, e.g., diaminomethyleneamino, (H₂N)₂C═NH—) and those bonded at either of the nitrogen atoms carrying a formal single bond (the “1-” and/or “3”-positions of the guanidine, e.g., H₂N—C(═NH)—NH—). The hydrogen atoms at either nitrogen can be replaced with a suitable substituent, such as loweralkyl, aryl, or loweraralkyl.

4.1.13 Amidino

As used herein, the term “amidino” refers to the moieties R—C(═N)—NR′— (the radical being at the “N₁” nitrogen) and R(NR′)C═N— (the radical being at the “N²” nitrogen), where R and R′ can be hydrogen, loweralkyl, aryl, or loweraralkyl.

4.1.14 Imino and Oximino

The term “imino” refers to the group —C(═NR)—, where R can be hydrogen or optionally substituted loweralkyl, aryl, heteroaryl, or heteroaralkyl respectively. The terms “iminoloweralkyl”, “iminocycloalkyl”, “iminocycloheteroalkyl”, “iminoaralkyl”, “iminoheteroaralkyl”, “(cycloalkyl)iminoalkyl”, “(cycloiminoalkyl)alkyl”, “(cycloiminoheteroalkyl)alkyl”, and “(cycloheteroalkyl)iminoalkyl” refer to optionally substituted loweralkyl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl groups that include an imino group, respectively.

The term “oximino” refers to the group —C(═NOR)—, where R can be hydrogen (“hydroximino”) or optionally substituted loweralkyl, aryl, heteroaryl, or heteroaralkyl respectively. The terms “oximinoloweralkyl”, “oximinocycloalkyl”, “oximinocycloheteroalkyl”, “oximininoaralkyl”, “oximinoheteroaralkyl”, “(cycloalkyl)oximinoalkyl”, “(cyclooximinoalkyl)alkyl”, “(cyclooximinoheteroalkyl)alkyl”, and (cycloheteroalkyl)oximininoalkyl” refer to optionally substituted loweralkyl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl groups that include an oximino group, respectively.

4.1.15 Methylene and Methine

The term “methylene” as used herein refers to an unsubstituted, monosubstituted, or disubstituted carbon atom having a formal sp³ hybridization (i.e., —CRR′—, where R and R′ are hydrogen or independent substituents).

The term “methine” as used herein refers to an unsubstituted or carbon atom having a formal sp² hybridization (Le., —CR═ or ═CR—, where R is hydrogen a substituent).

4.2 Compounds of the Invention

The present invention provides compounds that have useful agonist and/or antagonist activity with respect to mammalian estrogen receptors in addition to compounds, compositions, and methods useful for treating estrogen receptor-mediated disorders in mammals. More particularly, the compounds of the present invention have been found to possess a surprising degree of activity with respect to the α- and β-isoforms of human estrogen receptor. Thus, the compounds, compositions, and methods described herein have utility in preventing and/or treating a wide variety of estrogen receptor-mediated disorders including, but not limited to, osteoporosis, breast cancer, uterine cancer, and congestive heart disease.

In a first aspect, the present invention provides compounds having the structure (Compound 1):

and its pharmaceutically acceptable salts. X₁ and X₂ are selected independently from the group consisting of nitrogen and oxygen such that if one of X₁ and X₂ is nitrogen, then the other of X₁ and X₂ is oxygen to form thereby an isoxazole ring structure. Thus, the generic structure shown above encompasses the following regioisomers:

depending on the identities of X₁ and X₂. R₁ and R₃ are selected independently from the group consisting of optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl. R₂ is selected from the group consisting of hydrogen, halo, cyano, nitro, thio, amino, carboxyl, formyl, and optionally substituted loweralkyl, loweralkylcarbonyloxy, arylcarbonyloxy, heteroarylcarbonyloxy, cycloalkylcarbonyloxy, cycloheteroalkylcarbonyloxy, aralkycarbonyloxy, heteroaralkylcarbonyloxy, (cycloalkyl)alkylcarbonyloxy, (cycloheteroalkyl)alkylcarbonyloxy, loweralkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, cycloalkylcarbonyl, cycloheteroalkylcarbonyl, aralkycarbonyl, heteroaralkylcarbonyl, (cycloalkyl)alkylcarbonyl, (cycloheteroalkyl)alkylcarbonyl, loweralkylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, cycloalkylaminocarbonyl, (cycloalkyl)alkylaminocarbonyl, cycloheteroalkylaminocarbonyl, (cycloheteroalkyl)alkylaminocarbonyl, loweralkylcarbonylamino, arylcarbonylamino, heteroarylcarbonylamino, cycloalkylcarbonylamino, cycloheteroalkylcarbonylamino, aralkylcarbonylamino, heteroaralkylcarbonylamino, (cycloalkyl)alkylcarbonylamino, (cycloheteroalkyl)alkylcarbonylamino, loweralkylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino, loweralkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, cycloalkylsulfonyl, cycloheteroalkylsulfonyl, aralkylsulfonyl, heteroaralkylsulfonyl, (cycloalkyl)alkylsulfonyl, (cycloheteroalkyl)alkylsulfonyl, loweralkylsulfinyl, arylsulfinyl, heteroarylsulfinyl, cycloalkylsulfinyl, cycloheteroalkylsulfinyl, aralkylsulfinyl, heteroaralkylsulfinyl, (cycloalkyl)alkylsulfinyl, (cycloheteroalkyl)alkylsulfinyl, loweralkyloxy, aryloxy, heteroaryloxy, cycloalkyloxy, cycloheteroalkyloxy, aralkyloxy, heteroaralkyloxy, (cycloalkyl)alkyloxy, and (cycloheteroalkyl)alkyloxy, loweralkylthio, arylthio, heteroarylthio, cycloalkylthio, cycloheteroalkylthio, aralkylthio, heteroaralkylthio, (cycloalkyl)alkylthio, (cycloheteroalkyl)alkylthio, loweralkylthiocarbonyl, arylthiocarbonyl, heteroarylthiocarbonyl, cycloalkylthiocarbonyl, cycloheteroalkylthiocarbonyl, aralkythiocarbonyloxythiocarbonyl, heteroaralkylthiocarbonyl, (cycloalkyl)alkylthiocarbonyl, (cycloheteroalkyl)alkylthiocarbonyl, heteroarylcarbonylthio, cycloalkylcarbonylthio, cycloheteroalkylcarbonylthio, aralkycarbonylthiooxycarbonylthio, heteroaralkylcarbonylthio, (cycloalkyl)alkylcarbonylthio, (cycloheteroalkyl)alkylcarbonylthio, loweralkyloxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, cycloalkyloxycarbonyl, cycloheteroalkyloxycarbonyl, aralkyoxycarbonyl, heteroaralkyloxycarbonyl, (cycloalkyl)alkyloxycarbonyl, (cycloheteroalkyl)alkyloxycarbonyl, iminoloweralkyl, iminocycloalkyl, iminocycloheteroalkyl, iminoaralkyl, iminoheteroaralkyl, (cycloalkyl)iminoalkyl, (cycloheteroalkyl)iminoalkyl, (cycloiminoalkyl)alkyl, (cycloiminoheteroalkyl)alkyl, oximinoloweralkyl, oximinocycloalkyl, oximinocycloheteroalkyl, oximinoaralkyl, oximinoheteroaralkyl, (cycloalkyl)oximinoalkyl, (cyclooximinoalkyl)alkyl, (cyclooximinoheteroalkyl)alkyl, and (cycloheteroalkyl)oximinoalkyl.

In one embodiment, R₁ and R₃ are selected independently from the group consisting of optionally substituted cycloalkyl, cycloheteroalkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl. Examples of such groups include without limitation cyclohexyl, piperidinyl, adamantyl, and quinuclidyl, each optionally substituted. Other examples include cyclohexylmethyl, 2-cyclohexylethyl, and adamantylmethyl, again, each optionally substituted. In another embodiment, R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. More particular embodiments of the invention are those for which R₁ and R₃ are selected independently from the group consisting of optionally substituted heteroaryl and heteroaralkyl, such as pyridinyl, hydroxypyridyl, methoxypyridyl, pyridylmethyl, and the like.

Alternatively, R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl. In more specific embodiments, R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl and at least one of R₁ and R₃ is substituted with at least one hydroxyl, alkyloxy, aryloxy, thio, alkylthio, or arylthio group. Still more specific embodiments are those for which R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl and at least one of R₁ and R₃ is substituted with at least one hydroxyl, alkyloxy, aryloxy, thio, alkylthio, or arylthio group are those wherein at least one of R₁ and R₃ is selected independently from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl and include the substitutions just listed. Examples of useful groups include without limitation 4-hydoxyphenyl, phenylmethyl, 4-hydroxyphenymethyl, 3-hydroxyphenylmethyl, 2-thio-4-hydroxyphenylmethyl, 2-(4-hydroxyphenyl)ethyl, phenyloxy)methyl, 4-methoxyphenyl, 2-hydroxyphenyl, 3-(phenylthio)-4-hydroxyphenyl, and 3-methylphenyl-4-hydroxyphenyl. In a still more specific embodiment, the present invention includes compounds of the structure shown for Compound 1 for which R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl such that at least one of R₁ and R₃ is substituted with at least one hydroxyl, alkyloxy, aryloxy, thio, alkylthio, or arylthio group and at least one of R₁ and R₃ is selected independently from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, and further wherein at least one of R₁ and R₃ is substituted optionally with a substituent selected from the group consisting of halogen, nitro, cyano, loweralkyl, halolowerlalkyl, loweralkyloxy, haloloweralkyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, alkylsulfonylamino, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, lowerakylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, and heteroaralkylaminocarbonyl. Yet more specific embodiments includes those just recited for which at least one of R₁ and R₃ is further substituted optionally with a substituent selected from the group consisting of halogen, nitro, cyano, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkylthio, aminocarbonyl, and loweralkylsulfinyl. Examples of specific useful groups of this embodiment include without limitation 2-methyl-4-hydroxyphenyl, 2-aminocarbonyl-4-hydroxyphenyl, 4-methylsulfonylaminophenyl, 3-aminocarbonyl-4-hydroxyphenyl, 3-aminocarbonyl-4-methoxyphenyl, 3-chloro-4-hydroxyphenyl, 4-methylcarbonyloxyphenyl, 3-n-hexyl-4-hydroxyphenyl, 4-n-propylcarbonyloxyphenyl, 3-ethyl-4-hydroxyphenyl, 2-methylsulfinyl-4-hydroxyphenyl, 2-ethyl-4-hydroxyphenyl, 2-carboxy-4-hydroxyphenyl, 3-fluoro-4-hydroxyphenyl, 2-iodo-4-hydroxyphenyl, 2n-butyl-4-hydroxyphenyl, 2-trifluoromethoxyphenyl, and 4-fluorophenyl.

In other embodiments of the present invention, Compound 1 above includes compounds in R₂ is selected from the group consisting of hydrogen, halo, and optionally substituted loweralkyl, haloloweralkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, aryloxyalkyl, arylthioalkyl, arylcarbonyl, heteroarylcarbonyl, loweralkylcarbonyl, aminocarbonyl, arylaminocarbonyl, loweralkylaminocarbonyl, aralkylaminocarbonyl, (heterocycloloweralkyl)alkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, (cycloloweralkyl)aminocarbonyl, formyl, amino, loweralkylamino, and alkenyl. Particular examples of these embodiments include those for which R₂ is selected from the group consisting of hydrogen and halo. Other particular examples of these embodiments are those in which R₂ is selected from the group consisting of optionally substituted phenyl, phenylloweralkyl, hydroxyphenyl, loweralkyloxyphenyl, haloloweralkylsulfonylloweralkyloxyphenyl, diloweralkylaminoloweralkyloxyphenyl, (cycloaminoloweralkyl)loweralkyloxyphenyl, and (heterocycloalkyl)loweralkyloxyphenyl. Specific examples of such groups include phenylmethyl, 4-hydroxyphenyl, 2-(piperidin-1-yl)ethyloxyphenyl, 4-hydroxyphenyloxymethyl, and 2-(piperidin-1-yl)ethyloxyphenylmethyl. Still other particular embodiments are those for which R₂ is selected from the group consisting of optionally substituted loweralkyl, haloloweralkyl, hydroxyalkyl, phenyloxyloweralkyl, hydroxyphenyloweralkyl, haloloweralkylsulfonylloweralkyl, and phenylthioloweralkyl.

In still other embodiments of Compound 1 above R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl. Examples of R₂ substituents within this embodiment having useful properties include, but are not limited to, 4-(2-piperidin-1-ylethyloxy)phenylcarbonyl, 4-hydroxyphenylcarbonyl, (phenylmethyl)aminocarbonyl, 3-(2-oxopyrrolidin-1-yl)propylaminocarbonyl, di-n-butylaminocarbonyl, (4-hydroxyphenylmethyl)aminocarbonyl, (pyridin-3-ylmethyl)aminocarbonyl, (pyridin-2-ylmethyl)aminocarbonyl, dimethylaminocarbonyl, ethylaminocarbonyl, 4-(2-morpholinoethyloxy)phenylcarbonyl, 4-(3-dimethylaminopropyloxy)phenylcarbonyl, cyclopropylaminocarbonyl, cyclobutylaminocarbonyl, 4-(2-dimethylaminoethyloxy)phenylcarbonyl, 4-[2-(benzylmethylamino)ethyloxy]phenylcarbonyl, 4-(1-methylpiperidin-3-ylmethyloxy)phenylcarbonyl, 4-[2-(1-methylpyrrolidin-2-yl)ethyloxy]phenylcarbonyl, 4-[2-(4-methylpiperazin-1-yl)ethyloxy]phenylcarbonyl, 4-(1-methylpiperidin-4-ylmethyloxy)phenylcarbonyl, 2-chlorophenylcarbonyl, 3-chlorophenylcarbonyl, 4-chlorophenylcarbonyl, 3-nitrophenylcarbonyl, 4-nitrophenylcarbonyl, 3,4-dichlorophenylcarbonyl, 4-n-butylphenylcarbonyl, 3-hydroxyphenylcarbonyl, 2-hydroxyphenylcarbonyl, 4-methoxyphenylcarbonyl, 3-(2-piperidin-1-ylethyloxy)phenylcarbonyl, 3-(2-diethylaminoethyloxy)phenylcarbonyl, 3-[2-(pyrrolidin-1-yl)ethyloxy]phenylcarbonyl, 3-(1-methylpiperidin-3-ylmethyloxy)phenylcarbonyl, and 3-(2-dimethylaminoethyloxy)phenylcarbonyl.

In other embodiments, the compounds, compositions, and methods provided by the present invention include those compounds having the structure of Compound 1 above for which R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl, and R₁ and R₃ are selected independently from the group consisting of optionally substituted cycloalkyl, cycloheteroalkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl. Still other embodiments include those for which R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl, and R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. Of the latter embodiments, more specific embodiments include those for which R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl, and, still more particularly, those compounds wherein R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl, R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl, and at least one of R₁ and R₃ is selected independently from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, and, more specifically those compounds having the just-described substitution pattern wherein at least one of R₁ and R₃ is substituted with at least one hydroxyl or thio group. Yet more specific embodiments are those for which R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl, R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl, at least one of R₁ and R₃ is selected independently from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, at least one of R₁ and R₃ is substituted with at least one hydroxyl or thio group, and at least one of R₁ and R₃ is substituted optionally with a substituent selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, and heteroaralkylaminocarbonyl. Examples of particularly useful substituents are provided above.

In a second aspect, the present invention provide compounds having the general structure shown below (Compound 2):

and their pharmaceutically acceptable salts. X₃ and X₄ are selected independently from the group consisting of nitrogen and oxygen such that if one of X₃ and X₄ is nitrogen, then the other of X₃ and X₄ is oxygen to form thereby an isoxazole ring structure, Thus Compound 2 above will be recognized to include the general structures:

X₅ is —(X₁₀)_(n)—, wherein n is an integer between 1 and 3 and X₁₀, for each value of n, is selected independently from the group consisting of oxygen, —SO_(x)— where x is and integer between 0 and 2, nitrogen, nitrogen substituted with optionally substituted loweralkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, arylcarbonyl, alkylcarbonyl, aralkylcarbonyl, heteroarylcarbonyl, heteroaralkylcarbonyl, and methylene or methine, each optionally substituted from the group consisting of halo, cyano, nitro, thio, amino, carboxyl, formyl, and optionally substituted loweralkyl, loweralkylcarbonyloxy, arylcarbonyloxy, heteroarylcarbonyloxy, cycloalkylcarbonyloxy, cycloheteroalkylcarbonyloxy, aralkycarbonyloxy, heteroaralkylcarbonyloxy, (cycloalkyl)alkylcarbonyloxy, (cycloheteroalkyl)alkylcarbonyloxy, loweralkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, cycloalkylcarbonyl, cycloheteroalkylcarbonyl, aralkycarbonyl, heteroaralkylcarbonyl, (cycloalkyl)alkylcarbonyl, (cycloheteroalkyl)alkylcarbonyl, loweralkylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, loweralkylcarbonylamino, arylcarbonylamino, heteroarylcarbonylamino, cycloalkylcarbonylamino, cycloheteroalkylcarbonylamino, aralkylcarbonylamino, heteroaralkylcarbonylamino, (cycloalkyl)alkylcarbonylamino, (cycloheteroalkyl)alkylcarbonylamino, loweralkylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino, loweralkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, cycloalkylsulfonyl, cycloheteroalkylsulfonyl, aralkylsulfonyl, heteroaralkylsulfonyl, (cycloalkyl)alkylsulfonyl, (cycloheteroalkyl)alkylsulfonyl, loweralkylsulfinyl, arylsulfinyl, heteroarylsulfinyl, cycloalkylsulfinyl, cycloheteroalkylsulfinyl, aralkylsulfinyl, heteroaralkylsulfinyl, (cycloalkyl)alkylsulfinyl, (cycloheteroalkyl)alkylsulfinyl, loweralkyloxy, aryloxy, heteroaryloxy, cycloalkyloxy, cycloheteroalkyloxy, aralkyloxy, heteroaralkyloxy, (cycloalkyl)alkyloxy, and (cycloheteroalkyl)alkyloxy, loweralkylthio, arylthio, heteroarylthio, cycloalkylthio, cycloheteroalkylthio, aralkylthio, heteroaralkylthio, (cycloalkyl)alkylthio, (cycloheteroalkyl)alkylthio, loweralkylthiocarbonyl, arylthiocarbonyl, heteroarylthiocarbonyl, cycloalkylthiocarbonyl, cycloheteroalkylthiocarbonyl, aralkythiocarbonyloxlthiocarbonyl, heteroaralkylthiocarbonyl, (cycloalkyl)alkylthiocarbonyl, (cycloheteroalkyl)alkylthiocarbonyl, heteroarylcarbonylthio, cycloalkylcarbonylthio, cycloheteroalkylcarbonylthio, aralkycarbonylthiooxycarbonylthio, heteroaralkylcarbonylthio, (cycloalkyl)alkylcarbonylthio, (cycloheteroalkyl)alkylcarbonylthio, loweralkyloxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, cycloalkyloxycarbonyl, cycloheteroalkyloxycarbonyl, aralkyoxycarbonyloxloxycarbonyl, heteroaralkyloxycarbonyl, (cycloalkyl)alkyloxycarbonyl, (cycloheteroalkyl)alkyloxycarbonyl, iminoloweralkyl, iminocycloalkyl, iminocycloheteroalkyl, iminoaralkyl, iminoheteroaralkyl, (cycloalkyl)iminoalkyl, and (cycloheteroalkyl)iminoalkyl. X₆-X₉ are selected independently from the group consisting of oxygen, sulfur, sulfinyl, nitrogen, and optionally substituted methine, and R₄ is selected from the group consisting of optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl.

Some embodiments of the present invention include those structures having the general form shown in Compound 2 above for which n is 1 and X₁₀ is selected from the group consisting of nitrogen, optionally substituted nitrogen, and optionally substituted methylene or methine. Such embodiments will be recognized as including ring systems that are completely delocalized as well as ring systems that are not completely delocalized. More specific embodiments include those structures of Compound 2 for which n is 1 and X₁₀ is selected from the group consisting of nitrogen, optionally substituted nitrogen, and optionally substituted methylene or methine and R₄ is selected from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. Still more specific embodiments are those having the substitution pattern just described and for which R₄ is optionally substituted aryl or aralkyl. Yet more specific embodiments of the invention include compounds wherein n is 1 and X₁₀ is selected from the group consisting of nitrogen, optionally substituted nitrogen, and optionally substituted methylene or methine, R₄ is optionally substituted aryl or aralkyl, and R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. In some embodiments having the structure of Compound 2 above, n is 1 and X₁₀ is selected from the group consisting of nitrogen, optionally substituted nitrogen, and optionally substituted methylene or methine, R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl wherein R₄ is optionally substituted aryl or aralkyl, R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety and R₄ is further substituted optionally with a moiety selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, cyano, nitro, amino, loweralkylamino, and heteroaralkylaminocarbonyl.

In another embodiment, the present invention provides compounds having the structure of Compound 2 above for which n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine. More specific embodiments include those for which n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine and R₄ is selected from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. Also provided are embodiments in which n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine and R₄ is optionally substituted aryl or aralkyl. Yet more specific embodiments having this latter substitution pattern are those for which R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Still more particular embodiments are those wherein n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine and R₄ is optionally substituted aryl or aralkyl, R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl and R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Other, more particular embodiments are those in which n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine, R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety and R₄ is further substituted optionally with a moiety selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, cyano, nitro, amino, loweralkylamino, and heteroaralkylaminocarbonyl.

Still other embodiments of the present invention include compounds of the general formula of Compound 2 for which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine. More particular embodiments are those for which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine and at least one of X₆-X₉ is methine substituted with a moiety selected from the group consisting of loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, and heteroarylcarbonyl. Still more particular embodiments having the structural pattern just described include those in which X₇ is methine substituted with hydroxy or loweralkyloxy.

In other embodiments of the invention having the general formula of Compound 2, X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine, n is 1 and X₁₀ is selected from the group consisting of nitrogen, optionally substituted nitrogen, and optionally substituted methylene or methine. More specific embodiments are those in which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine, n is 1 and X₁₀ is selected from the group consisting of nitrogen, optionally substituted nitrogen, and optionally substituted methylene or methine, and R₄ is selected from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. Still more specific embodiments include those for which X₆-X₉, n, and X₁₀ have the values just defined and R₄ is optionally substituted aryl or aralkyl. In yet more specific embodiments, X₆-X₉, n and X₁₀ have the values just defined, R₄ is optionally substituted aryl or aralkyl, and R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Other embodiments are those for which X₆-X₉, n, X₁₀ and R₄ have the values and substituents just defined, but more specifically R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl. Still more embodiments are those for which X₆-X₉, n, X₁₀ and R₄ have the values and substituents just defined and R₄ is further substituted optionally with a moiety selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, cyano, nitro, amino, loweralkylamino, and heteroaralkylaminocarbonyl.

Yet other embodiments of the invention including the compounds of the general formula of Compound 2 are those in which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine, n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine. More specific embodiments are those in which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine, n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine, and R₄ is selected from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl. Still more specific embodiments include those for which X₆-X₉, n, and X₁₀ have the values just defined and R₄ is optionally substituted aryl or aralkyl. In yet more specific embodiments, X₆-X₉, n, X₁₀ and R₄ have the values just defined and R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety. Yet more specific embodiments are those for which X₆-X₉, n, X₁₀ and R₄ have the values and substituents just defined, but more particularly in which R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl. Other embodiments having the general structure of Compound 2 are those for which X₆-X₉ are selected independently from the group consisting of nitrogen and optionally substituted methine, n is 2 and each X₁₀ is selected independently from the group consisting of nitrogen, optionally substituted nitrogen, optionally substituted methylene, and optionally substituted methine, R₄ is selected from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl, R₄ includes at least one hydroxyl, thio, or optionally substituted loweralkyloxy, aryloxy, heteroaryloxy, loweralkylthio, arylthio, heteroarylthio, loweralkylcarbonyl, arylcarbonyl, or heteroarylcarbonyl moiety, and R₄ is further substituted optionally with a moiety selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, cyano, nitro, amino, loweralkylamino, and heteroaralkylaminocarbonyl.

4.3 Synthesis of the Compounds of the Invention

The compounds of the present invention can be synthesized using techniques and materials known to those of skill in the art (Carey and Sundberg 1983; Carey and Sundberg 1983; Greene and Wuts 1991; March 1992). Starting materials for the compounds of the invention may be obtained using standard techniques and commercially available precursor materials, such as those available from Aldrich Chemical Co. (Milwaukee, Wis.), Sigma Chemical Co. (St. Louis, Mo.), Lancaster Synthesis (Windham, N.H.), Apin Chemicals, Ltd. (New Brunswick, N.J.), Ryan Scientific (Columbia, S.C.), Maybridge (Cornwall, England), Arcos (Pittsburgh, Pa.), and Trans World Chemicals (Rockville, Md.)

The procedures described herein for synthesizing the compounds of the invention may include one or more steps of protection and deprotection (e.g., the formation and removal of acetal groups) (Greene and Wuts 1991). In addition, the synthetic procedures disclosed below can include various purifications, such as column chromatography, flash chromatography, thin-layer chromatography (“TLC”), recrystallization, distillation, high-pressure liquid chromatography (“HPLC”) and the like. Also, various techniques well known in the chemical arts for the identification and quantification of chemical reaction products, such as proton and carbon-13 nuclear magnetic resonance (¹H and ¹³C NMR), infrared and ultraviolet spectroscopy (“IR” and “UV”), X-ray crystallography, elemental analysis (“EA”). HPLC and mass spectroscopy (“MS”) can be used for identification, quantitation and purification as well.

Scheme 1 is a general scheme for synthesis of isoxazoles.

Step A is a Claisen-type condensation, in which X is a leaving group such as —OR (R=alkyl, aryl, arlkyl, heteroaryl, or heteroaralkyl), or halogen. When X is —OR and R is alkyl (e.g., X is methoxy or ethoxy) the reaction of 1a and 1b to produce 1c can be done using procedures known to those of skill in the organic chemistry arts (Tietze and Eicher 1989). When X is halogen, e.g., Cl, a typical procedure involves deprotonation of ketone 1a with a base such as lithium bis(trimethylsilyl)amide (LiHMDS) followed by addition of 1b. Suitable solvents for performing such reactions will be familiar to those of skill in the organic chemistry arts. Examples of suitable solvents include ether-type solvents such as tetrahydrofuran (“THF”), diethyl ether (H₃CH₂COCH₂CH₃), or aliphatic and aromatic hydrocarbon solvents such as cyclohexane (C₆H₁₂) and toluene (C₇H₈). Typical reaction temperatures range from −78° C. to +25° C. and the reaction times from 6 hours (“h”) to 20 h. Step B is a cycloaddition reaction to form the desired isoxazole. In a typical procedure, a mixture of 1c, two equivalents of hydroxyamine hydrochloride, and three a crude material that can be purified to afford substantially pure compound 1d. If R₁ and R₂ are not identical, then a mixture of regioisomers is formed. In some cases, protecting groups have to be removed to obtain targeted compound 1e, as illustrated by Step C. Protection and deprotection will depend greatly on the chemical properties of the molecule and its functional groups; appropriate methods for protection and deprotection are well known in the organic chemistry arts (Greene and Wuts 1991). For example, when R₁ is methoxyphenyl, three methods can be used for demethylation: 1) reaction of aqueous hydrogen bromide (HBr) and glacial acetic acid with Id with heating to 100-120° C. for 6 to 16 h; 2) reaction of ethane thiol, aluminum trichloride, and 1d in dichloroethane with stirring at room temperature (“rt”) for 16 to 72 h; or 3) stirring boron tribromide with 1d in dichloromethane at room temperature overnight.

Scheme 2 describes an alternative method to synthesize compound 1c of Scheme 1.

Step A above can be performed using various methods familiar to those of skill in the organic chemistry arts. For example, at least three well known methods can be used to convert 2a to 1c: 1) deprotonation of 2a with a base such as sodium hydride (NaH) in an aprotic solvent such as dimethylformamide (“DMF”) or THF, followed by reaction of the resulting anion with an electrophile R₃X, wherein X is a leaving group such as halogen or MsO; or 2) compound 2a is reacted with R₃X, potassium carbonate and tetrabutylammonium bromide in DMF while stirring at rt −100° C. for 6 to 24 h. If R₃ is paraalkyloxyphenyl, then a plumbate method can applied (Craig, Holder et al. 1979; Pinhey, Holder et al. 1979).

Regiospecific synthesis of the isoxazoles of the invention can be performed using known methods. One example of such a method is shown in Scheme 3 below (Perkins, Beam et al.):

Scheme 4 describes an alternative method to synthesize compound 1d in Scheme 1.

Formation of isoxazoles 4a from 1,3-diketone 2a (Step A) can be performed using Step B of Scheme 1. Bromination of isoxazole 4a (Step B) can be accomplished by addition of bromine in chloroform solution to a solution of 4a under temperatures from rt−55° C. for a period between 0.5 to 2 h to form 4-bromoisoxazole 4b. A variety of substituents at the R₃ can be introduced to 4-bromoisoxazole 4b to form the desired product 1d (Step C) as will be apparent to those of skill in the organic chemistry arts. For example, metal-halogen exchange followed by trapping the resulting isoxazole anion with an electrophile can be used to attach R₃. This can be done, for example, by reaction of bromoisoxazole 4b in THF solution at −78° C. with n-BuLi. The mixture is stirred at −78° C. for 1 h. The desired electrophile corresponding to R₃ is then added, and the reaction is warmed to 0° C.-rt over a period between 2 to 16 h. Suitable electrophiles include, but are not limited to, the following: alkyl halides, disulfides, iodine, N-chlorosuccinimide, tosyl nitrile, ethyl chloroformate, acid chlorides, carbon dioxide, dimethylformamide, aldehydes, Weinreb amides and sulfonyl chlorides.

Alternatively, a 4-carboxyisoxazole (i e., R₃=—CO₂ ⁻) can be obtained if carbon dioxide is used as the electrophile. The carboxylic acid can be further transformed to various esters, amides, and ketones. To form an amide at R₃, typical amide bond formation condition can be applied. For example, the corresponding carboxylic acid can be activated with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (“EDC”) HCl salt, 1-hydroxybenzotriazole (“HOBt”), and Hünig's base and mixed with a primary or secondary amine in THF or DMF. The reaction is complete in 6 to 16 hours at rt. Suzuki coupling can also be used to introduce aryl and alkenyl moieties at R₃ (Miyaura, Author et al. 1979; Miyaura and Suzuki 1979). The Ullmann reaction can be used to introduce aryloxy groups at R₃ (Knight; Semmelhack, Author et al.). Moieties having C—N and C—O bonds at 4-position of isoxazole 4b can be achieved by applying palladium catalyzed coupling reactions (Palucki, Wolfe et al. 1996; Wolfe and Buchwald 1996; Wolfe, Wagaw et al. 1996).

Scheme 5 illustrates more specific modifications at 4-position of the isoxazole.

Starting material 5a can be synthesized by methods described above. The linker Z can be —CH₂—, —O—, —S—, —SO₂—, —NR′R″—, —(C═O)—, —(C═NOR)—, or the aryl group can be attached to the isoxazole core directly. In the Scheme above, R₃ is a phenol protecting group that can be removed selectively (Greene and Wuts 1991) as shown in Step A. The free hydroxyl group can be derivatized using known methods and materials (Step B). However, other suitable groups such as, but not limited to, thiols, protected thiols, amines, and the like can be synthesized using analogous methodologies. One specific methodology is described with respect to Scheme 6 below where Z is —SO₂— or C═O)— and Y is O, S, or N. The index can be 1, 2, or 3, and R₄ is —NR′R″ or —N(R′)(C═O)R″. In one example, sodium hydride was mixed with HY(CH₂)_(n)R₄, to generate the nucleophile and added to 6a in THF or DMF solution at a temperature between rt and 60° C. and completed within 2 to 8 h.

Specific modifications at 5-position of the isoxazole can be performed using the methodologies described with Scheme 7 below:

where E is alkyl, aryl, aralkyl, halo, cyano, amido, carboxy, sulfide, and sulfoxide. Starting material 7a can be synthesized according to methods described above. The functional group E is introduced using the methods described in Step C of Scheme 4 above. Modifications at the 4-position of the isoxazole can be made, for example, using the methods described with respect to Scheme 8.

Starting material 8a was synthesized according to methods described in Scheme 1. Bromination at the methyl position was performed using N-bromosuccinimide in carbon tetrachloride. Alkylation to form derivatives of 8c where R₄ is —OR, —SR or —NRR′ can be conducted with appropriate nucleophile in a suitable solvent (e.g., DMF or THF) at temperatures ranging between rt and 100° C.

The procedures described above can be applied to solid phase methodologies as well. The actual implementation depends, of course, on the details of the desired products and starting materials. One example of a suitable methodology, where R₁ is hydroxyphenyl, is shown in Scheme 9.

In step A, commercially available hydroxylated Rink resin (Calbiochem, La Jolla, Calif.) is reacted with mesyl chloride and Hünig's base in methylene chloride (CH₂Cl₂) at 0° C. with warming to room temperature over a two-hour period. Next, 4-hydroxyacetophenone and Hünig's base are reacted with the resin product in methylene chloride at room temperature overnight provides resin-bound ketone 9a. Reaction of the bound ketone with an ester bearing the R₃ substituent (R₃CO₂R) and base (e.g., potassium tert-butoxide, t-BuOK and dibenzo-18-crown-6) in a suitable solvent (e.g., THF) at 70° C. for six hours (Step B) provides diketone 9b. Deprotonation of 9b, using, e.g., tert-butyl ammonium iodide (“TBAI”) under mild conditions (70° C. overnight) and the R₂ substituent bearing a suitable leaving group (e.g., halogen, tosylate, mesylate) provides 9c. Cyclization of 9c to form the desired isoxazole (resin-bound regioisomers 9d and 9e) can be performed by reaction of the bound diketone with H₂NOH.HCl and Hünig's base in a suitable solvent (e.g., dimethylsulfoxide, (“DMSO”)) at 70° C. for fifteen hours. Cleavage from the resin can be performed under mild conditions (e.g., reaction with 5% trifluoroacetic acid. (“TFA”) in methylene chloride) provides the final products 9d and 9e.

4.4 Biological Activity

The activities of the compounds of the invention to function as estrogen receptor agonists or antagonists can be determined using a wide variety of assays known to those having skill in the biochemistry, medicinal chemistry, and endochrinology arts. Several useful assays are described generally in this Section 4.4. Specific examples are described in Section 5.2 below.

4.4.1 Assays for Estrogen Receptor Modulating Activity In Vivo and Ex Vivo

4.4.1.1 Allen-Doisy Test for Estrogenicity

This test (described in greater detail in Section 5.2.1.1 below) is used to evaluate a test compound for estrogenic activity, and, more specifically, the ability of a test compound to induce an estrogenic cornification of vaginal epithelium (Allen and Doisy 1923; Mühlbock 1940; Terenius 1971). Test compounds are formulated and administered subcutaneously to mature, ovariectomized female rats in test group. In the third week after bilateral ovariectomy, the rats are primed with a single subcutaneous dose of estradiol to ensure maintenance of sensitivity and greater uniformity of response. In the fourth week, 7 days after priming, the test compounds are administered. The compounds are given in three equal doses over two days (evening of the first day and morning and evening of the second day). Vaginal smears are then prepared twice daily for the following three days. The extent of cornified and nucleated epithelial cells, as well as of leucocytes are evaluated for each of the smears.

4.4.1.2 Anti-Allen-Doisy Test for Anti-Estrogenicity

This test (described in greater detail in Section 5.2.1.2 below) is used to evaluate a test compound for anti-estrogenic activity by observation of cornification of the vaginal epithelium of in ovariectornized rats after administration of a test compound (Allen and Doisy 1923; Mühlbock 1940; Terenius 1971). Evaluation of anti-estrogenic activity is performed using mature female rats which, two weeks after bilateral ovariectomy, are treated with estradiol to induce a cornification of the vaginal epithelial. This was followed by administration of the test compound in a suitable formulation daily for 10 days. Vaginal smears are prepared daily, starting on the first day of test compound administration and proceeding until one day following the last administration of test compound. The extent of cornified and nucleated epithelial cells and leucocytes is evaluated for each of the smears as above.

4.4.1.3 Immature Rat Uterotrophic Bioassay for Estrogenicity and Anti-Estrogenicity

Changes in uterine weight in response to estrogenic stimulation can be used to evaluate the estrogenic characteristics of test compounds on uterine tissues (Reel, Lamb et al. 1996; Ashby, Odum et al. 1997). In one example, described in Section 5.2.1.3 below, immature female rats having low endogenous levels of estrogen are dosed with test compound (subcutaneously) daily for 3 days. Compounds are formulated as appropriate for subcutaneous injection. As a control, 17-beta-estradiol is administered alone to one dose group. Vehicle control dose groups are also included in the study. Twenty-four hours after the last treatment, the animals are necropsied, and their uteri excised, nicked, blotted and weighed to. Any statistically significant increases in uterine weight in a particular dose group as compared to the vehicle control group demonstrate evidence of estrogenicity.

4.4.1.4 Estrogen Receptor Antagonist Efficacy In MCF-7 Xenograft Model

This test (described in detail in Section 5.2.1.4 below) is used to evaluate the ability of a compound to antagonize the growth of an estrogen-dependent breast MCF-7 tumor in vivo. Female Ncr-nu mice are implanted subcutaneously with an MCF-7 mammary tumor from an existing in vivo passage. A 17-β-estradiol pellet is implanted on the side opposite the tumor implant on the same day. Treatment with test compound begins when tumors have reached a certain minimum size (e.g., 75-200 mg). The test compound is administered subcutaneously on a daily basis and the animals are subjected to daily mortality checks. Body weights and tumor volume are determined twice a week starting the first day of treatment. Dosing continues until the tumors reach 1,000 mm³. Mice with tumors larger than 4,000 mg, or with ulcerated tumors, are sacrificed prior to the day of the study determination. The tumor weights of animals in the treatment group are compared to those in the untreated control group as well as those given the estradiol pellet alone.

4.4.1.5 OVX Rat Model

This model evaluates the ability of a compound to reverse the decrease in bone density and increase in cholesterol levels resulting from ovariectomy. One example of such a model is described in Section 5.2.1.5. Three-month old female rats are ovariectornized, and test compounds are administered daily by subcutaneous route beginning one day post-surgery. Sham operated animals and ovariectornized animals with vehicle control administered are used as control groups. After 28 days of treatment, the rats are weighed, the overall body weight gains obtained, and the animals euthanized. Characteristics indicative of estrogenic activity, such as blood bone markers (e.g., osteocalcin, bone-specific alkaline phosphatase), total cholesterol, and urine markers (e.g., deoxypyridinoline, creatinine) are measured in addition to uterine weight. Both tibiae and femurs are removed from the test animals for analysis, such as the measurement of bone mineral density. A comparison of the ovariectornized and test vehicle animals to the sham and ovariectornized control animals allows a determination of the tissue specific estrogenic/anti-estrogenic effects of the test compounds.

4.4.2 Assays for Estrogen Receptor Modulating Activity In Vitro

4.4.2.1 ERα/ERβ Binding Assays

For evaluation of ERα/ERβ receptor binding affinity, a homogeneous scintillation proximity assay is used (described in Sections 5.2.2.1 and 5.2.2.2 below). 96-well plates are coated with a solution of either ERα or ERβ. After coating, the plates are washed with PBS. The receptor solution is added to the coated plates, and the plates are incubated. For library screening, [³H]estradiol is combined with the test compounds in the wells of the 96-well plate. Non-specific binding of the radio-ligand is determined by adding estradiol to one of the wells as a competitor. The plates are gently shaken to mix the reagents and a sample from each of the wells is then transferred to the pre-coated ERα or ERβ plates. The plates are sealed and incubated, and the receptor-bound estradiol read directly after incubation using a scintillation counter to determine test compound activity. If estimates of both bound and free ligand are desired, supernatant can be removed and counted separately in a liquid scintillation counter.

4.4.2.2 ERα/ERβ Transactivation Assays

The estrogenicity of the compounds of the invention can be evaluated in an in vitro bioassay using Chinese hamster ovary (“CHO”) cells that have been stably co-transfected with the human estrogen receptor (“hER”), the rat oxytocin promoter (“RO”) and the luciferase reporter gene (“LUC”) as described in Section 5.2.2.3 below. The estrogen transactivation activity (potency ratio) of a test compound to inhibit transactivation of the enzyme luciferase as mediated by the estrogen receptor is compared with a standard and the pure estrogen antagonist.

4.4.2.3 MCF-7 Cell Proliferation Assays

MCF-7 cells are a common line of breast cancer cells used to determine in vitro estrogen receptor agonist/antagonist activity (MacGregor and Jordan 1998). The effect of a test compound on the proliferation of MCF-7 cells, as measured by the incorporation of 5-bromo-2′-deoxyuridine (“BrdU”) in a chemiluminescent assay format, can be used to determine the relative agonist/antagonist activity of the test compound. MCF-7 cells (ATCC HTB-22) are mainatined in log-phase culture. The cells are plated and incubated in phenol-free medium to avoid external sources of estrogenic stimulus (MacGregor and Jordan 1998). The test compound is added at varying concentrations to determine an IC₅₀. for the compound. To determine agonist activity, the assay system is kept free of estrogen or estrogen-acting sources. To determine antagonist activity, controlled amounts of estrogen are added.

4.5 Pharmaceutical Compositions

The compounds of the present invention can be used in the form of salts derived from inorganic or organic acids. These salts include, but are not limited to, the following: acetate, adipate, alginate, citrate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, camphorate, camphorsulfonate, digluconate, cyclopentanepro-pionate, dodecylsulfate, ethanesulfonate, glucoheptanoate, glycerophosphate, hemi-sulfate, heptanoate, hexanoate, fumarate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, methanesulfonate, nicotinate, 2-napth-alenesulfonate, oxalate, pamoate, pectinate, sulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, p-toluenesulfonate and undecanoate. Also, any basic nitrogen-containing groups can be quaternized with agents such as loweralkyl halides, such as methyl, ethyl, propyl, and butyl chloride, bromides, and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl, and diamyl sulfates, long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides, aralkyl halides like benzyl and phenethyl bromides, and others. Water or oil-soluble or dispersible products are thereby obtained.

Examples of acids which may be employed to form pharmaceutically acceptable acid addition salts include such inorganic acids as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as oxalic acid, maleic acid, succinic acid and citric acid. Basic addition salts can be prepared in situ during the final isolation and purification of the compounds of the invention, or separately by reacting carboxylic acid moieties with a suitable base such as the hydroxide, carbonate or bicarbonate of a pharmaceutically acceptable metal cation or with ammonia, or an organic primary, secondary or tertiary amine. Pharmaceutically acceptable salts include, but are not limited to, cations based on the alkali and alkaline earth metals, such as sodium, lithium, potassium, calcium, magnesium, aluminum salts and the like, as well as nontoxic ammonium, quaternary ammonium, and amine cations, including, but not limited to ammonium, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, triethylamine, ethylamine, and the like. Other representative organic amines useful for the formation of base addition salts include diethylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine and the like.

Compounds of the present invention can be administered in a variety of ways including enteral, parenteral and topical routes of administration. For example, suitable modes of administration include oral, subcutaneous, transdermal, transmucosal, iontophoretic, intravenous, intramuscular, intraperitoneal, intranasal, subdural, rectal, vaginal, and the like.

In accordance with other embodiments of the present invention, there is provided a composition comprising an estrogen receptor-modulating compound of the present invention, together with a pharmaceutically acceptable carrier or excipient.

Suitable pharmaceutically acceptable excipients include processing agents and drug delivery modifiers and enhancers, such as, for example, calcium phosphate, magnesium stearate, talc, monosaccharides, disaccharides, starch, gelatin, cellulose, methyl cellulose, sodium carboxymethyl cellulose, dextrose, hydroxypropyl-β-cyclodextrin, polyvinylpyrrolidinone, low melting waxes, ion exchange resins, and the like, as well as combinations of any two or more thereof. Other suitable pharmaceutically acceptable excipients are described in Remington's Pharmaceutical Sciences, Mack Pub. Co., New Jersey (1991), which is incorporated herein by reference.

Pharmaceutical compositions containing estrogen receptor modulating compounds of the present invention may be in any form suitable for the intended method of administration, including, for example, a solution, a suspension, or an emulsion. Liquid carriers are typically used in preparing solutions, suspensions, and emulsions. Liquid carriers contemplated for use in the practice of the present invention include, for example, water, saline, pharmaceutically acceptable organic solvent(s), pharmaceutically acceptable oils or fats, and the like, as well as mixtures of two or more thereof. The liquid carrier may contain other suitable pharmaceutically acceptable additives such as solubilizers, emulsifiers, nutrients, buffers, preservatives, suspending agents, thickening agents, viscosity regulators, stabilizers, and the like. Suitable organic solvents include, for example, monohydric alcohols, such as ethanol, and polyhydric alcohols, such as glycols. Suitable oils include, for example, soybean oil, coconut oil, olive oil, safflower oil, cottonseed oil, and the like. For parenteral administration, the carrier can also be an oily ester such as ethyl oleate, isopropyl myristate, and the like. Compositions of the present invention may also be in the form of microparticles, microcapsules, liposomal encapsulates, and the like, as well as combinations of any two or more thereof.

The compounds of the present invention may be administered orally, parenterally, sublingually, by inhalation spray, rectally, vaginally, or topically in dosage unit formulations containing conventional nontoxic pharmaceutically acceptable carriers, adjuvants, and vehicles as desired. Topical administration may also involve the use of transdermal administration such as transdermal patches or ionophoresis devices. The term parenteral as used herein includes subcutaneous injections, intravenous, intramuscular, intrasternal injection, or infusion techniques.

Injectable preparations, for example, sterile injectable aqueous or oleaginous suspensions may be formulated according to the known art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a nontoxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-propanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution, and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid can be useful in the preparation of injectables.

Suppositories for rectal or vaginal administration of the drug can be prepared by mixing the drug with a suitable nonirritating excipient such as cocoa butter and polyethylene glycols that are solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum and release the drug.

Solid dosage forms for oral administration may include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active compound may be admixed with at least one inert diluent such as sucrose lactose or starch. Such dosage forms may also comprise, as is normal practice, additional substances other than inert diluents, e.g., lubricating agents such as magnesium stearate. In the case of capsules, tablets, and pills, the dosage forms may also comprise buffering agents. Tablets and pills can additionally be prepared with enteric coatings.

Liquid dosage forms for oral administration may include pharmaceutically acceptable emulsions, solutions, suspensions, syrups, and elixirs containing inert diluents commonly used in the art, such as water. Such compositions may also comprise adjuvants, such as wetting agents, emulsifying and suspending agents, cyclodextrins, and sweetening, flavoring, and perfuming agents.

The compounds of the present invention can also be administered in the form of liposomes. As is known in the art, liposomes are generally derived from phospholipids or other lipid substances. Liposomes are formed by mono- or multilamellar hydrated liquid crystals that are dispersed in an aqueous medium. Any non-toxic, physiologically acceptable and metabolizable lipid capable of forming liposomes can be used. The present compositions in liposome form can contain, in addition to a compound of the present invention, stabilizers, preservatives, excipients, and the like. The preferred lipids are the phospholipids and phosphatidyl cholines (lecithins), both natural and synthetic. Methods to form liposomes are known in the art (Prescott 1976).

While the compounds of the invention can be administered as the sole active pharmaceutical agent, they can also be used in combination with one or more other compound as described herein, and/or in combination with other agents used in the treatment and/or prevention of estrogen receptor-mediated disorders. Alternatively, the compounds of the present invention can be administered sequentially with one or more such agents to provide sustained therapeutic and prophylactic effects. Suitable agents include, but are not limited to, other SERMs as well as traditional estrogen agonists and antagonists. Representative agents useful in combination with the compounds of the invention for the treatment of estrogen receptor-mediated disorders include, for example, tamoxifen, 4-hydroxytamoxifen, raloxifene, toremifene, droloxifene, TAT-59, idoxifene, RU 58,688, EM 139, ICI 164,384, ICI 182,780, clomiphene, MER-25, DES, nafoxidene, CP-336,156, GW5638, LY139481, LY353581, zuclomiphene, enclomiphene, ethamoxytriphetol, delmadinone acetate, bisphosphonate, and the like. Other agents that can be combined with one or more of the compounds of the invention include aromatase inhibitors such as, but not limited to, 4-hydroxyandrostenedione, plomestane, exemestane, aminogluethimide, rogletimide, fadrozole, vorozole, letrozole, and anastrozole.

Still other agents useful for combination with the compounds of the invention include, but are not limited to antineoplastic agents, such as alkylating agents. Other classes of relevant antineoplastic agents include antibiotics, hormonal antineoplastics and antimetabolites. Examples of useful alkylating agents include alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines, such as a benzodizepa, carboquone, meturedepa and uredepa; ethylenimines and methylmelamines such as altretamine, triethylenemelamine, triethylenephosphoramide, triethylenethiophosphoramide and trimethylolmelamine; nitrogen mustards such as chlorambucil, chlornaphazine, cyclophosphamide, estramustine, iphosphamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichine, phenesterine, prednimustine, trofosfamide, and uracil mustard; nitroso ureas, such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, ranimustine, dacarbazine, mannomustine, mitobronitol, mitolactol and pipobroman. More such agents will be known to those having skill in the medicinal chemistry and oncology arts.

Additional agents suitable for combination with the compounds of the present invention include protein synthesis inhibitors such as abrin, aurintricarboxylic acid, chloramphenicol, colicin E3, cycloheximide, diphtheria toxin, edeine A, emetine, erythromycin, ethionine, fluoride, 5-fluorotryptophan, fusidic acid, guanylyl methylene diphosphonate and guanylyl imidodiphosphate, kanamycin, kasugamycin, kirromycin, and O-methyl threonine, modeccin, neomycin, norvaline, pactamycin, paromomycine, puromycin, ricin, α-sarcin, shiga toxin, showdomycin, sparsomycin, spectinomycin, streptomycin, tetracycline, thiostrepton and trimethoprim. Inhibitors of DNA synthesis, including alkylating agents such as dimethyl sulfate, mitomycin C, nitrogen and sulfur mustards, MNNG and NMS; intercalating agents such as acridine dyes, actinomycins, adriamycin, anthracenes, benzopyrene, ethidium bromide, propidium diiodide-intertwining, and agents such as distamycin and netropsin, can also be combined with compounds of the present invention in pharmaceutical compositions. DNA base analogs such as acyclovir, adenine, β-1-D-arabinoside, amethopterin, aminopterin, 2-aminopurine, aphidicolin, 8-azaguanine, azaserine, 6-azauracil, 2′-azido-2′-deoxynucleosides, 5-bromodeoxycytidine, cytosine, β-1-D-arabinoside, diazooxynorleucine, dideoxynucleosides, 5-fluorodeoxycytidine, 5-fluorodeoxyuridine, 5-fluorouracil, hydroxyurea and 6-mercaptopurine also can be used in combination therapies with the compounds of the invention. Topoisomerase inhibitors, such as coumermycin, nalidixic acid, novobiocin and oxolinic acid, inhibitors of cell division, including colcemide, colchicine, vinblastine and vincristine; and RNA synthesis inhibitors including actinomycin D, α-amanitine and other fungal amatoxins, cordycepin (3′-deoxyadenosine), dichlororibofuranosyl benzimidazole, rifampicine, streptovaricin and streptolydigin also can be combined with the compounds of the invention to provide pharmaceutical compositions. Still more such agents will be known to those having skill in the medicinal chemistry and oncology arts.

In addition, the compounds of the present invention can be used, either singly or in combination as described above, in combination with other modalities for preventing or treating estrogen receptor-mediated diseases or disorders. Such other treatment modalities include without limitation, surgery, radiation, hormone supplementation, and diet regulation. These can be performed sequentially (e.g., treatment with a compound of the invention following surgery or radiation) or in combination (e.g., in addition to a diet regimen).

In another embodiment, the present invention includes compounds and compositions in which a compound of the invention is either combined with, or covalently bound to, a cytotoxic agent bound to a targeting agent, such as a monoclonal antibody (e.g., a murine or humanized monoclonal antibody). It will be appreciated that the latter combination may allow the introduction of cytotoxic agents into cancer cells with greater specificity. Thus, the active form of the cytotoxic agent (i.e., the free form) will be present only in cells targeted by the antibody. Of course, the compounds of the invention may also be combined with monoclonal antibodies that have therapeutic activity against cancer.

The additional active agents may generally be employed in therapeutic amounts as indicated in the PHYSICIANS' DESK REFERENCE (PDR) 53rd Edition (1999), which is incorporated herein by reference, or such therapeutically useful amounts as would be known to one of ordinary skill in the art. The compounds of the invention and the other therapeutically active agents can be administered at the recommended maximum clinical dosage or at lower doses. Dosage levels of the active compounds in the compositions of the invention may be varied to obtain a desired therapeutic response depending on the route of administration, severity of the disease and the response of the patient. The combination can be administered as separate compositions or as a single dosage form containing both agents. When administered as a combination, the therapeutic agents can be formulated as separate compositions that are given at the same time or different times, or the therapeutic agents can be given as a single composition.

4.6 Treatment of Estrogen Receptor-Mediated Disorders

In accordance with yet other embodiments, the present invention provides methods for treating or preventing an estrogen receptor-mediated disorder in a human or animal subject in which an amount of an estrogen receptor-modulating compound of the invention that is effective to modulate estrogen receptor activity in the subject. Other embodiments provided methods for treating a cell or a estrogen receptor-mediated disorder in a human or animal subject, comprising administering to the cell or to the human or animal subject an amount of a compound or composition of the invention effective to modulate estrogen receptor activity in the cell or subject. Preferably, the subject will be a human or non-human animal subject. Modulation of estrogen receptor activity detectable suppression or up-regulation of estrogen receptor activity either as compared to a control or as compared to expected estrogen receptor activity.

Effective amounts of the compounds of the invention generally include any amount sufficient to detectably modulate estrogen receptor activity by any of the assays described herein, by other activity assays known to those having ordinary skill in the art, or by detecting prevention or alleviation of symptoms in a subject afflicted with a estrogen receptor-mediated disorder.

Estrogen receptor-mediated disorders that may be treated in accordance with the invention include any biological or medical disorder in which estrogen receptor activity is implicated or in which the inhibition of estrogen receptor potentiates or retards signaling through a pathway that is characteristically defective in the disease to be treated. The condition or disorder may either be caused or characterized by abnormal estrogen receptor activity. Representative estrogen receptor-mediated disorders include, for example, osteoporosis, atheroschlerosis, estrogen-mediated cancers (e.g., breast and endometrial cancer), Turner's syndrome, benign prostate hyperplasia (i.e., prostate enlargement), prostate cancer, elevated cholesterol, restenosis, endometriosis, uterine fribroid disease, skin and/or vagina atrophy, and Alzheimer's disease. Successful treatment of a subject in accordance with the invention may result in the prevention, inducement of a reduction in, or alleviation of symptoms in a subject afflicted with an estrogen receptor-mediated medical or biological disorder. Thus, for example, treatment can result in a reduction in breast or endometrial tumors and/or various clinical markers associated with such cancers. Likewise, treatment of Alzheimer's disease can result in a reduction in the rate of disease progression, detected, for example, by measuring a reduction in the rate of increase of dementia.

The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. It will be understood, however, that the specific dose level for any particular patient will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, route of administration, rate of excretion, drug combination, and the severity of the particular disease undergoing therapy. The prophylactically or therapeutically effective amount for a given situation can be readily determined by routine experimentation and is within the skill and judgment of the ordinary clinician.

For exemplary purposes of the present invention, a prophylactically or therapeutically effective dose will generally be from about 0.1 mg/kg/day to about 100 mg/kg/day, preferably from about 1 mg/kg/day to about 20 mg/kg/day, and most preferably from about 2 mg/kg/day to about 10 mg/kg/day of a estrogen receptor-modulating compound of the present invention, which may be administered in one or multiple doses.

5 EXAMPLES

The following Examples are provided to illustrate certain aspects of the present invention and to aid those of skill in the art in the art in practicing the invention. These Examples are in no way to be considered to limit the scope of the invention in any manner.

5.1 Preparation of Compounds of the Invention

5.1.1 General Procedures

All reactions were carried out under nitrogen or argon atmosphere. All reagents obtained from commercial sources were used without further purification. Anhydrous solvents were obtained from commercial sources and used without further drying. Separation and purification of the products were carried out using any or combination of the following methods. Flash column chromatography was performed with silica gel, 200-400 mesh, 60 A (Aldrich Chemical Company, Inc., Milwaukee, Wis.) or a Flash 40 chromatography system and KP-Sil, 60 A (Biotage, Charlottesville, Va.). Typical solvents employed were dichloromethane (DCM), methanol (MeOH), ethyl acetate (EtOAc), and hexane (Hex). Preparative TLC was conducted using 20×20 cm plates coated with Merch-EM Type-60, GF-254 silica gel. Preparative HPLC was performed with Dynamax System using a C-18 reversed phase column (Ranin).

Compounds of the present invention were characterized by LC/MS using either Waters Micromass Platform LCZ system (ionization mode: electron spray positive; column: HP-Eclipse XDB-C 18, 2×50 mm, buffer A: H₂O with 0.1% trifluoroacetic acid (TFA), buffer B: acetonitrile (MeCN) with 0.1% TFA, elution gradient: 5-95% buffer over 5 minute period, flow rate: 0.8 mL/min) or HP 1100 Series LC/MSD system (ionization mode: electron spray positive; column: HP-Eclipse XDB-C18, 2×50 mm, buffer A: H₂O with 0.1% TFA, buffer B: MeCN with 0.1% TFA, elution gradient: 5-95% buffer over 3.5 to 6 minute period, flow rate: 0.8 to 0.4 mL/min). Purity of the compounds evaluated by HPLC using a Waters Millennium chromatography system with a 2690 Separation Module (Milford, Mass.). The analytical columns were Alltima C-18 reversed phase, 4.6×250 mm from Alltech (Deerfield, Ill.). A gradient elution was used, typically starting with 5% MeCN/95% water and progressing to 100% MeCN over a period of 40 minuets. All solvents contained 0.1% TFA. Compounds were detected by ultraviolet light (UV) absorption at 214 nm. Some of the mass spectrometric analysis was performed on a Fisons Electrospray Mass Spectrometer. All masses are reported as those of the protonated parent ions unless otherwise noted. Nuclear magnetic resonance (NMR) analysis was performed with a Varian 300 MHz NMR (Palo Alto, Calif.). The spectral reference was either TMS or the known chemical shift of the solvent. Proton NMR (¹H NMR) data are reported as follows: chemical shift (δ) in ppm, multiplicity (s=singlet, d=doublet, t=triplet, q=quartet, p=pentet, m=multiplet, dd=doublet of doublet, br=broad), coupling constant (Hz), integration and assignment. Melting points were determined on a Laboratory Devices MEL-TEMP apparatus (Holliston, Mass.) and are reported uncorrected.

Compound names were generated using NOMENCLATOR (ChemInnovation Software, Inc., San Diego, Calif.).

5.1.2 Synthesis of Estrogen Receptor-Modulating Isoxazoles

5.1.2.1 Synthesis of 4-{5-[2-(4-hydroxyphenyl)ethyl]-4-benzylisoxazol-3-yl}phenol

This compound was synthesized by following Scheme 1 and Scheme 3 using 4′-methoxyacetophenone and methyl 3-(4-methoxyphenyl)propanoate for the Claisen condensation and benzyl bromide for the alkylation. Demethylation was performed using Method 3 described in Step C of Scheme 1. ESMS m/z 372 (MH⁺), C₂₄H₂₁NO₃=371 g/mol; HPLC purity=70%.

5.1.2.2 Synthesis of 4-[4-ethyl-5-(phenoxymethyl)isoxazol-3-yl]phenol

This compound was synthesized by following the methods described above for Scheme 1 using 1-(4-methoxyphenyl)butan-1-one and 2-phenoxyacetyl chloride as starting materials. Demethylation was performed using Method 3 described for Step C of Scheme 1. ESMS m/z 296 (MH⁺), C₁₈H₁₇NO₃=295 g/mol; HPLC purity=60%.

5.1.2.3 Synthesis of 4-[5-(4-hydroxyphenyl)-4-phenylisoxazol-3-yl]phenol

This compound was synthesized by following methods described above for Scheme 1 using 1-(4-methoxyphenyl)-2-phenylethan-1-one and 4-methoxybenzoyl chloride as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

¹H NMR (d₆-DMSO) δ7.60-7.36 (m, 9H), 7.00-6.90 (m, 4H); MS m/z 330 (MH⁺), C₂₁H₁₅NO₃=329 g/mol; HPLC purity=80%.

5.1.2.4 Synthesis of 4-[4-ethyl-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized by following methods described above for Scheme 1 using 1-(4-methoxyphenyl)butane-1-one and 4-methoxybenzoyl chloride as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

¹H NMR (d₆-DMSO) δ7.70 (d, J=8.24 Hz, 2H), 7.50 (d, J=8.24 Hz, 2H), 7.00 (dd, J=8.24, 2.2 Hz, 4H), 2.80 (q, J=6.75 Hz, 2H), 1.20 (t, J=6.75 Hz, 3H); GCMS m/z 281 (M+), C₁₇H₁₅NO₃=281 g/mol; HPLC purity=90%.

5.1.2.5 Synthesis of 4-{5-[2-(4-hydroxyphenyl)ethyl]-4-phenylisoxazol-3-yl}phenol

This compound was synthesized by following methods described above for Scheme 1 using 1-(4-methoxyphenyl)-2-phenylethan-1-one and 4-nitrophenyl 3-(4-methoxyphenyl)propanoate as starting materials. Demethylation was performed using Method 3 described for Step C in Scheme 1.

ESMS m/z 358 (MH⁺), C₂₃H₁₉NO₃=357 g/mol; HPLC purity=70%.

5.1.2.6 Synthesis of 4-[5-(4-hydroxyphenyl)-4-benzylisoxazol-3-yl]phenol

This compound was synthesized by following methods described above for Scheme 1 using 1-(4-methoxyphenyl)-3-phenylpropan-1-one and p-anisoyl chloride as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

¹H NMR (d₄-MeOH) δ7.60-7.20 (m, 9H), 7.01-6.80 (m, 4H), 4.20 (s, 2H); MS m/z 344 (MH+), C₂₂H₁₇NO₃=343 g/mol; HPLC purity=80%.

5.1.2.7 Synthesis of 4-[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]phenol

This compound was synthesized by following Scheme 1 and Scheme 3.

Step 1: To a solution of 4′-methoxyacetophenone in THF at −78° C. was added dropwise 1.5 eq. of [(CH₃)₂Si]₂NLi. The solution was stirred for 1 h at −78° C., followed by addition of 1.2 eq. of p-anisoyl chloride. The reaction mixture was stirred for 10 min at −78° C. and then for 22 h at rt, acidified with 10% citric acid, and extracted with EtOAc. The combined organic layers were washed with water and dried over Na₂SO₄. Remove of solvent in vacuo provided a crude solid which was purified by flash chromatography (CH₂Cl₂) to give 1,3-diketone as a white solid.

Step 2: Synthesis of p-methoxyphenyllead triacetate. To a solution of lead tetraacetate (0.73 equiv) in chloroform and dichloroacetic acid was added anisole (1.0 equiv.). The reaction mixture was allowed to stir at room temperature for 90 min. After this period the solution was washed with water and the organic layer was treated with hexane. The product precipitated out and was collected by filtration. The solid was taken up in chloroform and acetic acid. The resultant solution was stirred for 1 h and then washed with water. The later 2 steps were repeated and the chloroform layer was treated with hexane. This mixture was cooled to 2° C. for 24 h. The material that precipitated was collected by filtration and dried under vacuum to afford p-methoxyphenyllead triacetate.

Step 3: A mixture of the 1,3-diketone (1.0 equiv., obtained from step 1), p-methoxyphenyllead triacetate (1.1 equiv. obtained from step 2) and pyridine (3.3 equiv.) in chloroform was stirred at room temperature for 48 h. After this time had elapsed the reaction was diluted with chloroform, washed with water and 4M sulfuric acid. The aqueous washes were back extracted with chloroform. The combined organic extracts were washed with water, dried over magnesium sulfate, filtered and concentrated in vacuo. The crude product was purified by flash column chromatography (ethyl acetate/ hexane, 1:3) to afford an off white solid as 1,2,3-tris(4-methoxyphenyl)propane-1,3-dione.

Step 4: A mixture of the 1,3-diketone obtained in step 3 (1.0 equiv.), hydroxylamine hydrochloride (1.5 equiv.), pyridine (2.0 equiv.) and ethanol was heated to reflux overnight. Cooled to rt and removed solvent in vacuo. Water and ethyl acetate were added. The organic layer was separated, washed with dil. HCl, brine, dried, filtered and the solvent was concentrated in vacuo. The product 1-[4,5-bis(4-methoxyphenyl)isoxazol-3-yl]-4-methoxybenzene was obtained as an off white solid.

Step 5: Demethylation was performed using Method 1 described for Step C in Scheme 1 to afford the product 4-[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]phenol.

¹H NMR (d₆-DMSO) δ7.30 (d, J=9.0 Hz, 2H), 7.20 (d, J=9.0 Hz, 2H), 7.10 (d, J=9.0 Hz, 2H), 6.80 (d, J=9.0 Hz, 2H), 6.76 (d, J=9.0 Hz, 2H), 6.74 (d, J=9.0 Hz, 2H); MS m/z 346 (MH+), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=97%.

5.1.2.8 Synthesis of 4-[5-(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized by following the methods described above for Scheme 1 using 4′-acetophenone and p-anisoyl chloride as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

¹H NMR (d₆-DMSO) δ7.80-7.75 (m,4H), 7.5 (s, 1H), 6.99-6.90 (m, 4H); MS m/z 254 (MH+), C₁₅H₁₁NO₃=253 g/mol; HPLC purity=96%. 5.1.2.9 Synthesis of 4-{5-(4-hydroxyphenyl)-4-[4-(2-piperidylethoxy)phenyl]isoxazol-3-yl}phenol

This compound was synthesized by following Scheme 1, Scheme 3, and Scheme 5.

Step 1: Synthesis of 1,3-diketone is the same as Step 1 of the Example in Section 5.1.2.7.

Step 2: Synthesis of p-allyloxyphenyllead triacetate. Similar as Step 2 in Section 5.1.2.7 except allylphenyl ether was used as the starting material instead of p-anisole.

Step 3: Similar as Step 3 in Section 5.1.2.7, using p-allyloxyphenyllead triacetate instead of p-methoxyphenyllead triacetate.

Step 4: Formation of isoxazole skeleton is the same as Step 4 of Section 5.1.2.7. The product obtained from this step is 1-[3,5-bis(4-methoxyphenyl)isoxazol-4-yl]-4-prop-2-enyloxybenzene.

Step 5: Selective removal of the allyl protecting group. A mixture of the above isoxazole (1.0 equiv.), pyrrolidine (20 equiv.), triphenylphosphine (0.05 equiv.) and tetrakis(tiphenylphosphine) palladium(O) (0.05 equiv.) in THF was heated to reflux overnight. The solution was concentrated in vacuo and the crude material was purified by flash column chromatography (ethyl acetate/hexane 1:3). The product 4-[3,5-bis(4-methoxyphenyl)isoxazol-4-yl]phenol was obtained as a white solid.

Step 6: A mixture of the phenol (1.0 equiv., obtained from step 5), 1-(2-chloroethyl)piperidine monohydrochloride (1.2 equiv.) cesium carbonate (2.5 equiv.) in DMF (30 ml) was heated at 100° C. overnight. The solids were removed by filtration, the filtrate was concentrated in vacuo and the residue was taken up into ethyl acetate. The solution was washed with water, brine, dried over sodium sulfate, filtered and concentrated in vacuo to give 1-[3,5-bis(4-methoxyphenyl)isoxazol-4-yl]-4-(2-piperidylethoxy)benzene.

Step 7: Demethylation was performed using Method 2 described for Step C in Scheme I. To a solution of the isoxazole obtained from step 6 (1.0 equiv.) in dichloroethane was added aluminum chloride (5.0 equiv.) and ethane thiol (5.0 equiv.). The resultant mixture was stirred for 40 min at room temperature and quenched with THF, 20% HCl and water. A precipitate was formed and this was collected by filtration. After drying the product the material was taken up in methanol, treated with activated charcoal, filtered through sodium sulfate and concentrated in vacuo. Purification with flash chromatography followed by addition of HCl aq. and lyophilization, then afforded the product 4-{5-(4-hydroxyphenyl)-4-[4-2-piperidylethoxy)phenyl]isoxazol-3-yl}phenol as hydrochloride salt.

¹H NMR (d₄-MeOH) δ7.43 (d, J=9.0 Hz, 2H), 7.25 (d, J=8.0 Hz, 2H), 7.20 (d, J=9.0 Hz, 2H), 7.03 (d=9.0 Hz, 2H), 6.77 (d, J=8.0 Hz, 2H), 6.75 (d, J=8.0 Hz, 2H), 4.20 (t, J=5.5 Hz, 2H), 2.90 (t, J=5.5 Hz, 2H), 2.60-2.70 (m, 4H), 1.63-1.75 (m, 4H), 1.50-1.60 (m, 2H); MS m/z 457 (MH⁺, 100%), C₂₈H₂₈N₂O₄=456 g/mol; HPLC purity=98%.

5.1.2.10 Synthesis of 4-{4-(4-hydroxyphenyl)-3-[4-(2-piperidylethoxy)phenyl]isoxazol-5-yl}phenol

This compound was synthesized by following the procedures described above in Scheme 1, Scheme 3, and Scheme 7.

Step 1: Synthesis of 1,3-diketone is similar to that described in Step 1 of Section 5.1.2.7. To a solution of desoxyanisoin (1.0 equiv) in THF at −78° C. was added lithium bis(trimethylsilyl)amide (1.2 equiv.) dropwise. The resultant solution was allowed to stir for 40 min at −78° C. and a solution of p-allyloxybenzoyl chloride (1.1 equiv.) in THF was added dropwise. The reaction mixture was allowed to warm to room temperature slowly overnight to produce an orange colored solution. The mixture was diluted with 0.5N HCl, extracted with ethyl acetate, washed with 0.5N HCl, water, brine, dried over sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by recrystallization. This afforded some of the desired compound and the remaining residue was purified by flash column chromatography (ethyl acetate:hexanes 1:3) to afford the 1,3-diketone.

Step 2: Formation of isoxazole is the same as Step 4 of Section 5.1.2.7. The product afforded from this step is 4-methoxy-1-[4-(4-methoxyphenyl)-5-(4-prop-2-enyloxyphenyl)isoxazol-3-yl]benzene.

Step 3: Selective removal of the allyl protecting group. Same as Step 5 of Section 5.1.2.9. The product afforded from this step is 4-[3,4-bis(4-methoxyphenyl)isoxazol-5-yl]phenol.

Step 4: Alkylation. Same as Step 6 Section 5.1.2.9. The product afforded from this step is 4-methoxy-1-{4-(4-methoxyphenyl)-5-[4-(2-piperidylethoxy)phenyl]isoxazol-3-yl}benzene.

Step 5: Demethylation was performed using Method 2 described for Step C in Scheme 1 (see Step 7 of Section 5.1.2.9). The product was 4-{4-(4-hydroxyphenyl)-3-[4-(2-piperidylethoxy)phenyl]isoxazol-5-yl}phenol.

¹H NMR (d₆-DMSO) δ6.70-7.50 (m, 2H), 4.35-4.42 (m, 2H), 3.30-3.50 (m, 2H), 2.90-3.25 (m, 4H), 1.60-1.80 (m, 4H), 1.30-1.45 (m, 2H); MS m/z 457 (MH⁺, 100%), C₂₈H₂₈N₂O₄=456 g/mol; HPLC purity=98%.

5.1.2.11 Synthesis of 3-[4,5-bis(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized by following Scheme 1. Desoxyanisoin and m-anisoyl chloride were used as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1. The product obtained was an off-white solid.

MS m/z 346 (MH+), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=95%.

5.1.2.12 Synthesis of 2-[4,5-bis(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized by following Scheme 1. Desoxyanisoin and o-anisoyl chloride were used as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1. The product obtained was an off-white solid.

MS m/z 346 (MH+), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=96%.

5.1.2.13 Synthesis of 4-[3-(4-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol

This compound was synthesized by following Scheme 1. 1-(4-methoxyphenyl)propan-1-one and p-anisoyl chloride were used as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

ESMS m/z 268 (MH⁺), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=85%.

5.1.2.14 Synthesis of 4-[3-(4-hydroxyphenyl)-5-phenylisoxazol-4-yl]phenol

This compound was synthesized by following Scheme 1. Desoxyanisoin and benzoyl chloride were used as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

ESMS m/z 330 (MH⁺), C₂₁H₁₅NO₃=329 g/mol; HPLC purity=90%

5.1.2.15 Synthesis of 4-[5-(4-fluorophenyl)-3-(4-hydroxyphenyl)isoxazol-4-yl]phenol

This compound was synthesized by following Scheme 1. Desoxyanisoin and p-fluorobenzoyl chloride were used as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

ESMS m/z 348 (MH⁺), C₂₁H₁₄FNO₃=347 g/mol, HPLC purity=85%

5.1.2.16 Synthesis of 4-{4-(4-hydroxyphenyl)-5-[3-(trifluoromethoxy)phenyl]isoxazol-3-yl}phenol

This compound was synthesized by following Scheme 1. Desoxyanisoin and m-trifluoromethylbenzoyl chloride were used as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

ESMS m/z 414 (MH⁺), C₂₂H₁₄F₃NO₄=413 g/mol; HPLC purity=90%

5.1.2.17 Synthesis of 4-{4-(4-hydroxyphenyl)-5-[4-(trifluoromethoxy)phenyl]isoxazol-3-yl}phenol

This compound was synthesized by following Scheme b 1. Desoxyanisoin and p-trifluoromethylbenzoyl chloride were used as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

ESMS m/z 414 (MH⁺), C₂₂H₁₄F₃NO₄=413 g/mol; HPLC purity=90%

5.1.2.18 Synthesis of 4-[5-(4-hydroxyphenyl)-4-(phenoxymethyl)isoxazol-3-yl]phenol

This compound was synthesized by following the procedures described for Scheme 1 and Scheme 8.

Step 1: Formation of 1,3-diketone. Same as Step 1 of Section 5.1.2.7, except 1-(4-methoxyphenyl)propan-1-one was used as a starting material.

Step 2: Formation of the isoxazole skeleton. Same as Step 4 of Section 5.1.2.7. The product obtained from this step was 4-methoxy-1-[5-(4-methoxyphenyl)-4-methylisoxazol-3-yl]benzene.

Step 3: Bromination of 4-methylisoxazole. A suspension of the above 4-methylisoxazole (1.0 eq.), N-bromosuccinimide (NBS) (1.1 eq.), and PhCO₃H (catalytic amount) in CCl₄ was heated to reflux under argon for 2 h, cooled to rt and filtered. The filtrate was diluted with DCM, washed with 10% Na₂S₂O₃ and 10% NaHCO₃, dried and concentrated in vacuo. The resulting crude material was purified with flash column chromatography to give product 1-[4-(bromomethyl)-5-(4-methoxyphenyl)isoxazol-3-yl]-4-methoxybenzene.

Step 4: Alkylation. To a solution of phenol (1.1 eq.) in dry THF at 0° C. was added powder NaH (1.1 eq.) under argon. When the solution stopped bubbling, the above bromide was added to the solution and the mixture was stirred overnight at rt. The resulting solution was acidified with saturated NH₄Cl and extracted with ethyl ether. The combined organic layers were dried over Na₂SO₄ and rotary evaporated to give a white solid.

Step 5: Demethylation. The above white solid was converted to product 4-[5-(4-hydroxyphenyl)-4-(phenoxymethyl)isoxazol-3-yl]phenol using Method 1 described for Step C of Scheme 1.

ESMS m/e 360 (MH⁺), C₂₂H₁₇NO₄=359 g/mol; HPLC purity=90%.

5.1.2.19 Synthesis of 4-[5-(4-hydroxyphenyl)-4-(phenylthiomethyl)isoxazol-3-yl]phenol

This compound was synthesized by following the procedures described for Scheme 1 and Scheme 8.

Step 1-3 are the same as described for Steps 1-3 of Section 5.1.2.18, respectively.

Step 4: Alkylation. Same as Step 4 of Section 5.1.2.18, except thiophenol was used instead of phenol.

Step 5: Demethylation. Same as Step 5 of Section 5.1.2.18. The product obtained was 4-[5-(4-hydroxyphenyl)-4-(phenylthiomethyl)isoxazol-3-yl]phenol.

ESMS m/e 376 (MH⁺), C₂₂H₁₇NO₃S=375 g/mol; HPLC purity=90%.

5.1.2.20 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone

This compound was synthesized by following the procedures described above for Scheme 5.

Step 1: Same as Step 1 described in Section 5.1.2.7.

Step 2: Formation of isoxazole heterocycle. Same as Step 4 in Section 5.1.2.7. The product obtained from this step was 4-methoxy-1-[5-(4-methoxyphenyl)isoxazol-3-yl]benzene.

Step 3: Bromination. To a solution of the above isoxazole (1.0 eq.) in anhydrous CHCl₃ at reflux (70° C.) under argon was added dropwise bromine (1.01 eq.) in anhydrous CHCl₃ solution. The mixture was stirred for 50 min at reflux, followed by addition of 10% Na₂S₂O₃ in saturated NaHCO₃ aqueous solution. The aqueous-organic solution was separated and the aqueous layer was extracted with CH₂Cl₂. The combined organic phases were dried over Na₂SO₄ and rotary evaporated to give a yellow solid that was washed with ethyl acetate (“EtOAc”) to afford pale yellow solid as 1-[4-bromo-5-(4-methoxyphenyl)isoxazol-3-yl]-4-methoxybenzene in 92.5% yield.

Step 4: Acylation. To a solution of the above 4-bromoisoxazole (1.0 eq.) in anhydrous THF at −98° C. under argon was added n-BuLi (1.2 eq., 1.6 M in hexane). The resultant solution was stirred for 1 h at −98° C. and then transferred dropwise to a solution of 4-allyoxybenzoyl chloride (1.2 eq.) in THF at −78° C. through a double-tipped needle. The reaction mixture was stirred overnight at −78° C., diluted with water, and then acidified with 10% aqueous citric acid. The organic layer was dried over Na₂SO₄ and purified with flash chromatography (CH₂Cl₂) to give acylated product 3,5-bis(4-methoxyphenyl)isoxazol-4-yl 4-prop-2-enyloxyphenyl ketone as a pale yellow solid in 64% yield.

Step 5: Selective removal of the allyl protecting group. Same as Step 5 of Section 5.1.2.9.

Step 6: Alkylation. Same as Step 6 of Section 5.1.2.9.

Step 7: Demethylation was following Method 2 described for Step C of Scheme 1. To a solution of the compound obtained from the above step 6 in dry CH₂Cl₂ was added 5.0 equivalents of AICl₃ and 5.0 equivalents of ethane thiol (“EtSH”). The reaction mixture was stirred at rt for 1.2 h and the resultant slurry was then poured to ice-water. The organic layer was separated. The aqueous layer was extracted with EtOAc three times. The combined organic layers were dried over Na₂SO₄ and rotary evaporated in vacuo. The obtained reaction mixture which contained desired product and side product as mono-demethylated compound. The mixture was separated by HPLC to give product 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone in 22% yield after HPLC purification.

The product obtained from HPLC purification was dissolved in EtOAc/sat.NaHCO₃ (1:1) solution. The bilayer solution was shaken vigorously and separated. The aqueous layer was extracted with EtOAc several times. The combined organic layer was dried over MgSO₄ and rotary evaporated to give a yellow solid. The solid was then dissolved in cold acetone/conc. HCl (2:1) and the solution was rotary evaporated in vacuo to produce the HCl salt of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone as an off white powder. Recrystalization with methanol/water gave the salt as fine flaky crystals.

¹H NMR (d₆-DMSO) δ10.2 (s, 1H, OH), 9.93 (s, 1H, OH), 7.8-6.72 (m, 12H, 3Ph), 4.4 (br t, 2H, OCH₂—), 3.49 (m, 4H. N(CH₂)₂), 2.98 (br t, 2H, —CH₂—N), 1.79-1.39 (m, 6H. —(CH₂)₃). ESMS m/e 485 (MH⁺), C₂₉H₂₈N₂O₅=484 g/mol; HPLC purity=99%. mp 255° C. decomposed.

5.12.21 Synthesis of 5-(4-hydroxyphenyl)-3-(4-methoxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone

This compound was synthesized by following Scheme 5.

Steps 1-6 are exactly the same as the corresponding Steps of Section 5.1.2.20.

Step 7: Same as Step 7 of Section 5.1.2.20. Partial demethylation gave the title compound 5-(4-hydroxyphenyl)-3-(4-methoxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone which was isolated by HPLC.

ESMS m/e 499 (MH⁺), C₃₀H₃₀N₂O₅=498 g/mol; HPLC purity=97%.

5.1.2.22 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(hydroxypiperidyl)ethoxy]phenyl ketone

This compound was obtained as a side product of the reactions described in Section 5.1.2.20. The crude material obtained from Step 7 of Section 5.1.2.20 was dissolved in DMSO and left at rt overnight. HPLC analysis of this mixture showed formation of new compound that was 16 mass units higher than any of the products found in the reaction of Step 7 of Section 5.1.2.20. HPLC isolation thus afforded N-oxide 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(hydroxypiperidyl)ethoxy]phenyl ketone.

¹H NMR (d₆-DMSO): δ10.22 (s, 1H), 9.94 (s, 1H), 7.82-7.79 (d, J=8.76 Hz, 2H), 7.46-7.43 (d, J=8.76 Hz, 2H), 7.34-7.32 (d, J=8.30 Hz, 2H), 7.04-7.01 (d, J=8.76 Hz, 2H), 6.83-6.80 (d, J=8.76 Hz, 2H), 6.78-6.75 (d, J=8.30 Hz, 2H), 4.55 (br, 2H), 4.05 (br, 2H), 3.67 (br, 4H), 2.00-1.35 (m, 6H); LC/MS m/z 501 (MH⁺), C₂₉H₂₈N₂O₆=500 g/mol; HPLC purity=99%.

5.1.2.23 Synthesis of 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl 4-[2-(hydroxypiperidyl)ethoxyl]phenyl ketone

This compound was obtained as a side product of the synthesis described in Section 5.1.2.21. The crude material obtained from Step 7 was dissolved in DMSO and left at rt overnight. HPLC analysis of this mixture showed formation of new compound which was 16 mass units higher than any of the products characterized previously. HPLC isolation afforded 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl 4-[2-(hydroxypiperidyl)ethoxy]phenyl ketone.

ESMS m/e 515 (MH⁺), C₃₀H₃₀N₂O₆=514 g/mol); HPLC purity=88%.

5.1.2.24 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-hydroxyphenyl ketone

This compound was synthesized by following the procedures described for Scheme 5.

Steps 1-4 were performed exactly the same as corresponding Steps in Section 5.1.2.20.

Step 5: Deprotection was performed by following Method 3 described for Step C in Scheme 1. This step gave the desired product 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-hydroxyphenyl ketone.

ESMS m/e 374 (MH⁺), C₂₂H₁₅NO₅=373 g/mol; HPLC purity=90%.

5.1.2.25 Synthesis of 4-[4-bromo-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized by following the procedures described for Scheme 4.

Step 1-3 are exactly the same as the corresponding steps in Section 5.1.2.20.

Step 4: Demethylation was performed using Method 1 described for Step C in Scheme 1.

ESMS m/e 332/334 (MH⁺), C₁₅H₁₀BrNO₃=331/333 g/mol (1Br); HPLC purity=90%.

5.1.2.26 Synthesis of 4-[4-(bromomethyl)-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized by following the procedures described above for Scheme 1 and Scheme 8.

Steps 1-3 are same as corresponding steps in Section 5.1.2.20.

Step 4: Demethylation was following Method 3 described for Step C in Scheme 1. To a solution of above isoxazole in DCM at −78° C. was added dropwise 5 eq. boron tribromide (1M in DCM solution). The mixture was slowly warmed to rt and stirred under argon for 1.5 h. The reaction was quenched by adding water and neutralized to pH 5. Extracted with EtOAc, dried with Na₂SO₄ and concentrated in vacuo to give a crude material. Purification by HPLC afforded 10% of desired product.

ESMS m/e 346/348 (MH⁺, 100%), C₁₆H₁₂BrNO₃=345/347 g/mol (1Br); HPLC purity=80%.

5.1.2.27 Synthesis of 4-{5-(4-hydroxyphenyl)-4-[(4-hydroxyphenoxy)methyl]isoxazol-3-yl}phenol

This compound was synthesized by following the procedures described above for Scheme 1 and Scheme 8.

Steps 1, 2 and 3 are same as corresponding steps in Section 5.1.2.18.

Step 4: Alkylation. Same as step 4 of Section 5.1.2.18 except 4-(benzyloxy)phenol was used in the procedure. The product obtained form this step is 1-{[3,5-bis(4-methoxyphenyl)isoxazol-4-yl]methoxy}-4-(phenylmethoxy)benzene.

Step 5: Demethylation was following Method 3 described for Step C in Scheme 1. The product obtained was 4-{5-(4-hydroxyphenyl)-4-[(4-hydroxyphenoxy)methyl]isoxazol-3-yl}phenol.

ESMS m/e 376 (MH⁺), C₂₂H₁₇NO₅=375 g/mol; HPLC purity=80%.

5.1.2.28 Synthesis of 4-[4-(hydroxymethyl)-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was obtained as a side product in the synthesis of product in Section 5.1.2.27; isolation was achieved with HPLC.

ESMS m/z 284 (MH⁺), C₁₆H₁₃NO₄=283 g/mol, HPLC purity=99%.

5.1.2.29 Synthesis of 3-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol

This compound was synthesized by following the methods described in Scheme 1, using 6-methoxy-1-tetralone and p-anisoyl chloride as the starting materials. Demethylation was performed following Method 1 of Step C in Scheme 1.

ESMS m/e 280 (MH⁺), C₁₇H₁₃NO₃=279 g/mol; HPLC purity=90%.

5.1.2.30 Synthesis of 4-(7-methoxy-4,5-dihydronaphtho[1,2-c]isoxazol-3-yl)phenol

This compound was synthesized in the same manner as described in Section 5.1.2.29. Partial demethylation afforded mono-methylated product 4-(7-methoxy-4,5-dihydronaphtho[1,2-c]isoxazol-3-yl)phenol, which was isolated by HPLC to provide the desired product.

ESMS m/e 294 (MH⁺), C₁₈H₁₅NO₃=293 g/mol; HPLC purity=89%.

5.1.2.31 Synthesis of 3-[3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized in the same manner as described in Section 5.1.2.8 except 4′-methoxyacetophenone and m-anisoyl chloride were used as the starting materials.

ESMS m/e 254 (MH⁺), C₁₅H₁₁NO₃=253 g/mol; HPLC purity=90%.

5.1.2.32 Synthesis of 3-(4-hydroxyphenyl)naphtho[1,2-c]isoxazol-7-ol

This compound was synthesized by following the methods described in Scheme 1.

Step 1: Formation of 1,3-diketone. Same as Step 1 of Section 5.1.2.7 except 6-methoxy-1-tetralone and p-anisoyl chloride were used as the starting materials.

Step 2: Formation of isoxazole heterocycle. Same as Step 4 of Section 5.1.2.7. The product obtained from this step was 7-methoxy-3-(4-methoxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazole.

Step 3: Oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (“DDQ”). To the product of Step 2 in dry toluene was added DDQ (1.1 eq.). The solution was refluxed overnight, quenched with sat. NaHCO₃, K₂CO₃ and extracted with CH₂Cl₂. The combined organic layers were dried over Mg₂SO₄ and evaporated in vacuo to give a solid residue. Purification with flash column chromatography yield product 7-methoxy-3-(4-methoxyphenyl)naphtho[1,2-c]isoxazole.

Step 4: Demethylation was following Method 1 described for Step C in Scheme 1.

ESMS m/e 278 (MH⁺), C₁₇H₁₁NO₃=277 g/mol; HPLC purity=95%.

5.1.2.33 Synthesis of 3-(3-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol

This compound was synthesized in the same manner as described in Section 5.1.2.29 except m-anisoyl chloride was used as one of the starting materials.

ESMS m/e 280 (MH⁺), C₁₇H₁₃NO₃=279 g/mol; HPLC purity=90%.

5.1.2.34 Synthesis of 3-(2-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol

This compound was synthesized in the same manner as described in Section 5.1.2.29, except o-anisoyl chloride was used as one of the starting materials.

ESMS m/e 280 (MH⁺), C₁₇H₁₃NO₃=279 g/mol; HPLC purity=90%.

5.1.2.35 Synthesis of 3-[5-(3-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized in the same manner as described in Section 5.1.2.8, except 3′-methoxyacetophenone and m-anisoyl chloride were used as starting materials.

ESMS m/e 254 (MH⁺) C₁₅H₁₁NO₃=253 g/mol; HPLC purity=97%.

5.1.2.36 Synthesis of 2-[3-(3-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized in the same manner as described in Section 5.1.2.8, except 3′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/e 254 (MH⁺), C₁₅H₁₁NO₃=253 g/mol; HPLC purity=96%.

5.1.2.37 Synthesis of 2-[5-(2-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized in the same manner as described in Section 5.1.2.8 except 2′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/e 254 (MH⁺), C₁₅H₁₁NO₃=253 g/mol; HPLC purity=90%.

5.1.2.38 Synthesis of 3-[3-(3-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol

This compound was synthesized by following the procedures described for Scheme 1 and Scheme 3.

Step 1: Formation of 1,3-diketone is the same as Step 1 as described in Section 5.1.2.7 using 3′-methoxyacetophenone and m-anisoyl chloride as the starting materials.

Step 2: Alkylation. A THF solution of the above 1,3-diketone (1.0 eq.) was added dropwise to a suspension of sodium hydride (1.1 eq) in THF at 0° C. The mixture was stirred at rt for 30 min. followed by addition of iodomethane (1.1 eq.). The reaction mixture was stirred at rt overnight, poured into saturated NH₄Cl aq. and extracted with ether and DCM. The organic extracts were washed with brine, dried with MgSO₄ and concentrated in vacuo to give the product 1,3-bis(3-methoxyphenyl)-2-methylpropane-1,3-dione.

Step 3: Formation of isoxazole heterocycle. Same as Step 4 as described in Section 5.1.2.7. The product obtained from this step is 3-methoxy-1-[5-(3-methoxyphenyl)-4-methylisoxazol-3-yl]benzene.

Step 4: Demethylation was performed following Method 1 of Step C of Scheme 1 to give the desired product.

ESMS m/e 268 (MH⁺), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=94%.

5.1.2.39 Synthesis of 2-[3-(3-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol

This compound was synthesized in the same manner as described in Section 5.1.2.38, except 3′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/e 268 (MH⁺), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=90%.

5.1.2.40 Synthesis of 2-[3-(2-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol

This compound was synthesized in the same manner as described in Section 5.1.2.38, except 2′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/e 268 (MH⁺), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=90%.

5.1.2.41 Synthesis of 3-[4-ethyl-3-(3-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized by following the procedures described for Scheme 1 and Scheme 3.

Steps 1 was performed as the corresponding Step described in Section 5.1.2.38.

Step 2 alkylation procedure was performed as Step 2 of Section 5.1.2.38, using iodoethane as the alkylaing agent.

Steps 3 and 4 are exactly the same as the corresponding Steps described in Section 5.1.2.38. The product obtained was 3-[4-ethyl-3-(3-hydroxyphenyl)isoxazol-5-yl]phenol.

ESMS m/e 282 (MH⁺), C₁₇H₁₅NO₃=281 g/mol; HPLC purity=90%.

5.1.2.42 Synthesis of 2-[4-ethyl-3-(3-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized in the same manner described in Section 5.1.2.41, except 3′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/e 282 (MH⁺), C₁₇H₁₅NO₃=281 g/mol; HPLC purity=90%.

5.1.2.43 Synthesis of 2-[4-ethyl-3-(2-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized in the same manner described in Section 5.1.2.41, except 2′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/e 282 (MH⁺), C₁₇H₁₅NO₃=281 g/mol; HPLC purity=90%.

5.1.2.44 Synthesis of 3-[4-(4-hydroxyphenyl)-5-(3-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized in the same manner described in Section 5.1.2.7, except 3′-methoxyacetophenone and m-anisoyl chloride were used as starting materials.

ESMS m/z 346 (MH+), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=94%.

5.1.2.45 Synthesis of 2-[3-(3-hydroxyphenyl)-4-(4-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized in the same manner described in Section 5.1.2.7, except 3′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/z 346 (MH+), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=90%.

5.1.2.46 Synthesis of 2-[4-(4-hydroxyphenyl)-5-(2-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized in the same manner described in Section 5.1.2.2, except 2′-methoxyacetophenone and o-anisoyl chloride were used as starting materials.

ESMS m/z 346 (MH+), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=94%.

5.1.2.47 Synthesis of 3-(2-hydroxyphenyl)-4,5-dihydronaphtho[2,1-d]isoxazol-7-ol

This compound was synthesized in the same manner as described in Section 5.1.2.29, except 6-methoxy-1-tetralone and o-anisoyl chloride were used as starting materials. Demethylation was performed following Method 1 described in Step C of Scheme 1 to provide the desired product.

ESMS m/e 280 (MH⁺), C₁₇H₁₃NO₃=279 g/mol; HPLC purity=90%.

5.1.2.48 Synthesis of 2-(7-methoxy-4,5-dihydronaphtho[1,2-c]isoxazol-3-yl)phenol

This compound was synthesized in the same manner as described in Section 5.1.2.47. Partial demethylation afforded mono-methylated product 2-(7-methoxy-4,5-dihydronaphtho[1,2-c]isoxazol-3-yl)phenol.

ESMS m/e 294 (MH⁺), C₁₈H₁₅NO₃=293 g/mol; HPLC purity=95%.

5.1.2.49 Synthesis of 2-[5-(3-hydroxyphenyl)-4-methylisoxazol-3-yl]phenol

This compound is the regioisomer of the compound described in Section 5.1.2.39. Both regioisomers were obtained using the methods described in that Section, and the two regioisomers were separated by HPLC using a C₁₈ column (Reliasil-BDXC18, 10×50 mm, Ranin Dynamax) running a first buffer of H₂O/0.1% TFA and a second buffer of HCN/0.1% TFA through a gradient from 5-95% of the second buffer over a nine-minute period at a flow rate of ten ml/min.

ESMS m/e 268 (MH⁺), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=90%.

5.1.2.50 Synthesis of 2-[4-ethyl-5-(3-hydroxyphenyl)isoxazol-3-yl]phenol

This compound is the regioisomer of compound described in Section 5.1.2.42. Both regioisomers were obtained using the methods described in that Section, and the two regioisomers were separated by HPLC using a C₁₈ column (Reliasil-BDXC18, 10×50 mm, Ranin Dynamax) running a first buffer of H₂O/0.1% TFA and a second buffer of HCN/0.1% TFA through a gradient from 5-95% of the second buffer over a nine-minute period at a flow rate of ten ml/min.

ESMS m/e 282 (MH⁺), C₁₇H₁₅NO₃=281 g/mol; HPLC purity=90%.

5.1.2.51 Synthesis of 2-[4-(4-hydroxyphenyl)-5-(3-hydroxyphenyl)isoxazol-3-yl]phenol

This compound is the regioisomer of the compound described in Section 5.1.2.45. Both regioisomers were obtained using the methods described in that Section, and the two regioisomers were separated by HPLC using a C₁₈ column (Reliasil-BDXC18, 10×50 mm, Ranin Dynamax) running a first buffer of H₂O/0.1% TFA and a second buffer of HCN/0.1% TFA through a gradient from 5-95% of the second buffer over a nine-minute period at a flow rate of ten ml/min.

ESMS m/z 346 (MH⁺), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=90%.

5.1.2.52 Synthesis of 3-(5-(3-hydroxyphenyl)-4-{[4-(2-piperidylethoxy)phenyl]methyl}isoxazol-3-yl)phenol

This compound is synthesized as described in Section 5.1.2.20. The starting materials used were 3′-methoxyacetophenone, m-anisoyl chloride, and 4-allyloxybenzyl bromide.

ESMS m/z 471 (MH+), C₂₉H₃₀N₂O₄=470 g/mol; HPLC purity=88.3%.

5.1.2.53 Synthesis of 3-(3-hydroxyphenyl)-5-(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except m-anisoyl chloride as one of the starting materials. The product was obtained as hydrochloric acid salt in a form of an off-white powder.

¹H NMR (d₆-DMSO) δ7.84 (d, J=8.76 Hz, 2H, ArH, regioisomer 1), 7.82 (d, J=8.76 Hz, 2H, ArH, regioisomer 2), 7.44 (d, J=8.76 Hz, 2H, ArH, regioisomer 2), 7.36 (d, J=8.76 Hz, 2H, ArH, regioisomer 1), 7.30-7.09 (m, 2H, ArH), 7.04-7.02 (m, 2H, ArH), 6.94-6.79 (m, 4H, ArH), 4.41 (br t, 2H, OCH2), 3.46 (br m, 4H, NCH2), 2.79(br m, 2H, NCH2), 1.80-1.32 (m, 6H, CH2); ESMS m/e 485 (MH⁺), C₂₉H₂₈N₂O₅=484 g/mol; HPLC purity=100%.

5.1.2.54 Synthesis of 2-[3-(4-hydroxyphenyl)-4-phenylisoxazol-5-yl]phenol

This compound was synthesized as described in Section 5.1.2.3, except o-anisoyl chloride was used as one of the starting materials.

MS m/z 330 (MH+), C₂₁H₁₅NO₃=329 g/mol; HPLC purity=90%.

5.1.2.55 Synthesis of 3-[3-(4-hydroxyphenyl)-4-phenylisoxazol-5-yl]phenol

This compound was synthesized as described in Section 5.1.2.54, except m-anisoyl chloride was used as one of the starting materials.

MS m/z 330 (MH+), C₂₁H₁₅NO₃=329 g/mol; HPLC purity=90%.

5.1.2.56 Synthesis of 2-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized as described in Section 5.1.2.54, except o-anisoyl chloride was used as one of the starting materials.

ESMS m/z 282 (MH+), C₁₇H₁₅NO₃=281 g/mol; HPLC purity=90%.

5.1.2.57 Synthesis of 3-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized as described in Section 5.1.2.54, except m-anisoyl chloride was used as one of the starting materials.

ESMS m/z 282 (MH+), C₁₇H₁₅NO₃=281 g/mol; HPLC purity=90%.

5.1.2.58 Synthesis of 2-[3-(4-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol

This compound was synthesized as described in Section 5.1.2.13, except using o-anisoyl chloride as one of the starting materials.

ESMS m/z 268 (MH+), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=90%.

5.1.2.59 Synthesis of 3-[3-(4-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol

This compound was synthesized as described in Section 5.1.2.13, except m-anisoyl chloride was used as one of the starting materials.

ESMS m/z 268 (MH+), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=90%.

5.1.2.60 Synthesis of 2-[3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized as described in Section 5.1.2.8, except o-anisoyl chloride was used as one of the starting materials.

ESMS m/z 254 (MH+), C₁₅H₁₁NO₃=253 g/mol; HPLC purity=90%.

5.1.2.61 Synthesis of 4-(5-(4-hydroxyphenyl)-4-{[4-(2-piperidylethoxy)phenyl]methyl}isoxazol-3-yl)phenol

This compound was synthesized as described in Section 5.1.2.20. The starting materials used are 4′-methoxyacetophenone, p-anisoyl chloride, and 4-allyloxybenzyl bromide.

¹H NMR (d₆-DMSO & CDCl₃): δ1.8-2.05 (2H, m), 2.62-2.75 (4H, m), 2.78-2.85 (2H, m) 3.32-3.38 (2H, m), 3.51 (2H, d, J=11.9 Hz), 3.88 (2H, s), 4.35 (2H, t, J=4.5 Hz), 6.71 (2H, d, J=8.6 Hz), 6.74 (2H, d, J=8.6 Hz), 6.76 (2H, d, J=8.8 Hz), 6.96 (2H, d, J=8.6 Hz), 7.22 (2H, d, J=8.6 Hz), 7.35 (2H, d, J=8.8 Hz); ESMS m/z 471 (MH+), C₂₉H₃₀N₂O₄=470 g/mol; HPLC purity=85.4%.

5.1.2.62 Synthesis of 2-[5-(4-hydroxyphenyl)-4-methylisoxazol-3-yl]phenol

This compound is the regioisomer of the compound synthesized as described in Section 5.1.2.58. Both regioisomers were obtained using the methods described in that Section and the two regioisomers were separated by HPLC using a C₁₈ column (Reliasil-BDXC18, 10×50 mm, Ranin Dynamax) running a first buffer of H₂O/0.1% TFA and a second buffer of HCN/0.1% TFA through a gradient from 5-95% of the second buffer over a nine-minute period at a flow rate of ten ml/min.

ESMS m/z 268 (MH+), C₁₆H₁₃NO₃=267 g/mol; HPLC purity=99%.

5.1.2.63 Synthesis of 1-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-d]isoxazol-8-ol

This compound was synthesized by following the procedures described in Scheme 1 using 7-methoxy-2-tetralone and phenyl 4′-allyloxybenzoate as starting materials. Demethylation was performed following Method 1 of Step C.

ESMS m/e 280 (MH⁺), C₁₇ H₁₃NO₃=279 g/mol; HPLC purity=92%.

5.1.2.64 Synthesis of 3-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-8-ol

This compound was synthesized as described in Section 5.1.2.29, except 7-methoxy-1-tetralone and p-anisoyl chloride were used as starting materials.

ESMS m/e 280 (MH⁺), C₁₇H₁₃NO₃=279 g/mol; HPLC purity=90%.

5.1.2.65 Synthesis of 3-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-6-ol

This compound was synthesized as described in Section 5.1.2.29, except using 5-methoxy-1-tetralone and p-anisoyl chloride as starting materials.

ESMS m/e 280 (MH⁺), C₁₇H₁₃NO₃=279 g/mol; HPLC purity=90%.

5.1.2.66 Synthesis of 4-[5-(4-hydroxyphenyl)-4-iodoisoxazol-3-yl]phenol

This compound was synthesized by following Scheme 4.

Steps 1-3 were performed as described for the corresponding steps described in Section 5.1.2.20 to afford 1-[4-bromo-5-(4-methoxyphenyl)isoxazol-3-yl]-4-methoxybenzene.

Step 4: To the above 4-bromoisoxazole in THF at −78° C. was added dropwise 1.1 eq. of n-BuLi solution (1.6 M in hexane). Maintained the reaction at −78° C. for 1 h followed by addition of 1.1 eq. of I₂ in THF solution. The reaction was warmed to rt and stirred overnight, poured into saturated NH₄Cl aq. and extracted with DCM. The organic extracts were washed with Na₂S₂O₃ aq., brine, dried with MgSO₄ and concentrated in vacuo to give 1-[4-iodo-5-(3-methoxyphenyl)isoxazol-3-yl]-3-methoxybenzene.

Step 5: Demethylation was following Method 1 described for Step C in Scheme 1.

¹H NMR [(CD₃)₂CO]: δ7.08 (m, 4H), 7.72 (d, J=8.4 Hz, 2H), 8.01 (d, J=8.6 Hz, 2H), 8.86 (s, 1H), 9.10 (s, 1H); ESMS m/z 380 (MH+), C₁₅H₁₀INO₃=379 g/mol; HPLC purity=85.8%.

5.1.2.67 Synthesis of 4-[4-chloro-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol

This compound was synthesized as described in Section 5.1.2.66 except, in step 4, N-chlorosuccinimide (NCS) was used as the electrophile to trap the isoxazole anion.

¹H NMR [(CD₃)₂CO]: δ7.09 (m, 4H), 7.82 (d, J=8.4 Hz, 2H), 7.98 (d, J=9.0 Hz, 2H), 9.70 (br s, 2H); ESMS m/z 288 (MH+), C₁₅H₁₀ClNO₃=287 g/mol; HPLC purity=96.0%.

5.1.2.68 Synthesis of 3-(4-hydroxyphenyl)naphtho[1,2-c]isoxazol-8-ol

This compound was synthesized as described in Section 5.1.2.32, except 7-methoxy-1-tetralone and p-anisoyl chloride were used as starting materials.

ESMS m/e 278 (MH⁺), C₁₇H₁₁NO₃=277 g/mol; HPLC purity=80%.

5.1.2.69 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-benzylcarboxamide

This compound was synthesized by following the procedure described in Scheme 4.

Steps 1-3 were performed as the corresponding Steps in Section 5.1.2.20 to afford 1-[4-bromo-5-(4-methoxyphenyl)isoxazol-3-yl]-4-methoxybenzene.

Step 4: To the above 4-bromoisoxazole in THF at −78° C. was added dropwise 1.1 eq. of n-BuLi solution (1.6 M in hexane). Maintained the reaction at −78° C. for 1 h followed by blowing carbon dioxide gas from a gauge controlled cylinder for ca. 20 min. The reaction was warmed to rt carefully, poured into saturated NH₄Cl aq. and extracted with DCM. The organic extracts were washed with brine, dried with MgSO₄ and concentrated in vacuo to give 3,5-bis(3-methoxyphenyl)isoxazole-4-carboxylic acid.

Step 5: Amide bond formation. 4-carboxyisoxazole (obtained from step 4) was dissolved in THF and activated with EDC HCl salt/HOBt/DIEA (1.5:1.5:1.5) and allowed to stand at rt for 5 min. Benzylamine (1.5 equiv.) was then added. The reaction was allowed to stand at rt overnight, after which it was diluted with EtOAc and washed with 10% citric acid, 10% NaHCO₃, brine and solvent was removed. Residue was lyophilized in 90% MeCN/H₂O and sampled.

Products were purified by flash chromatography (EtOAc/petroleum ether) to give pure [3,5-bis(4-methoxyphenyl)isoxazol-4-yl]-N-benzamide.

Step 6: Demethylation procedure was described in Method 3 for Step C in Scheme 1.

¹H NMR (d₆-DMSO): δ4.39 (2H, d, J=5.86 Hz), 6.79 (2H, d, J=8.79 Hz), 6.83 (2H, d, J=8.79 Hz), 7.22-7.24 (1H, m), 7.26-7.32 (2H, m), 7.50 (2H, d, J=8.61 Hz), 7.56 (2H, d, J=8.79 Hz), 9.20 (1H, t, J=5.95 Hz), 9.87 (1H, s), 10.10 (1H, s); ESMS m/z 387 (MH+), C₂₃H₁₈N₂O₄=386 g/mol; HPLC purity=96.4%.

5.1.2.70 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N,N-dibutylcarboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, N,N-di-n-butyl amine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ0.48 (3H, t, J=7.33 Hz), 0.85 (2H, q, J=7.33 Hz), 0.90 (3H, t, J=7.33 Hz), 1.00 (2H, t, J=7.42 Hz), 1.23-1.31 (3H, m), 1.51 (2H, t, J=7.24 Hz), 2.86-2.91 (2H, m), 3.43-3.50 (1H, m), 6.86 (2H, d, J=8.61 Hz), 6.90 (2H, d, J=8.79 Hz), 7.51 (2H, d, J=8.79 Hz), 7.58 (2H, d, J=8.61 Hz), 9.93 (1H, s), 10.13 (1H, s); ESMS m/z 409 (M+H), C₂₄H₂₈N₂O₄=408 g/mol; HPLC purity=96.7%.

5.1.2.71 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-[3-(2-oxopyrrolidinyl)propyl]carboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, 1-(3-aminopropyl)pyrrolidin-2-one was used for amide bond formation.

¹H NMR (d₆-DMSO): δ1.60 (2H, t, J=7.05 Hz), 1.90 (2H, d, J=7.60 Hz), 2.19 (2H, d, J=8.06 Hz), 3.10 (2H, t, J=7.14 Hz), 3.16 (2H, q, J=6.59 Hz), 3.25 (2H, t, J=6.96 Hz), 3.87 (2H, d, J=8.79 Hz), 7.62 (2H, d, J=8.79 Hz), 7.54 (2H, d, J=8.79 Hz), 8.64 (1H, t, J=5.58 Hz), 9.88 (1H, s), 10.11 (1H, s); ESMS m/z 422 (M+H), C₂₃H₂₃N₃O₅=421 g/mol; HPLC purity=92.8%.

5.1.2.72 Synthesis of ′[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-(2-phenylethyl)carboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, benzethyl amine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ2.75 (2H, d, J=7.23 Hz), 7.46 (2H, d, J=6.72 Hz), 6.84 (2H, d, J=8.61 Hz ), 6.88 (2H, d, J=8.61 Hz), 7.12-7.20 (3H, m), 7.23-7.26 (2H, m), 7.49 (2H, d, J=8.61 Hz), 7.56 (2H, d, J=8.79 Hz), 8.76 (1H, t, J=5.49 Hz), 9.86 (1H, s), 10.10 (1H, s); ESMS m/z 401 (M+H), C₂₄H₂₀N₂O₄=400 g/mol; HPLC purity=82.0%.

5.1.2.73 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-[(4-hydroxyphenyl)methyl]carboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, p-methoxybenzyl amine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ4.28 (2 h, d, J=5.86 Hz), 6.68 (2H, d, J=8.43 Hz), 6.79 (2H, d, J=8.79 Hz), 6.82 (2H, d, J=8.79 Hz), 7.03 (2H, d, J=8.24 Hz), 7.49 (2H, d, J=8.97 Hz), 7.55 (2H, d,J=8.79 Hz), 9.08 (1H, t, J=5.86 Hz), 9.87 (1H, s), 10.10 (1H, s); ESMS m/z 403 (M+H), C₂₃H₁₈N₂O₅=402 g/mol; HPLC purity=93.0%.

5.1.2.74 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-(3-pyridylmethyl)carboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, 3-pyridylmethylamine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ4.42 (2H d, J=5.86 Hz), 6.79 (2H, d, J=8.79 Hz), 6.84 (2H, d, J=8.61 Hz), 7.34 (2H, dd, J=7.69 Hz, 4.76 Hz), 7.46 (2H, d, J=8.61 Hz), 7.53 (2H, d, J=8.79 Hz), 7.62 (2H, d, J=7.69 Hz), 9.28 (1H, t, J=5.86 Hz), 9.95 (1H, s), 10.20 (1H, s); ESMS m/z 388 (M+H), C₂₂H₁₇N₃O₄=387 g/mol; HPLC purity=92.7%.

5.1.2.75 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-(2-pyridylmethyl)carboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, 2-pyridylmethylamine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ4.49 (2H, d, J=6.04 Hz), 6.82 (2H, d, J=8.61 Hz), 6.86 (2H, d, J=8.61 Hz), 7.21 (1H, d, J=7.88 Hz), 7.29 (1H, dd, J=6.8 Hz, 5.0 Hz), 7.55 (2H, d, J=8.79 Hz), 7.63 (2H, d, J=8.79 Hz), 7.71 (1H, td, J=7.5 Hz, 1.65 Hz), 8.51 (1H, d, J=4.03 Hz), 9.29 (1H, t, J=5.86 Hz), 9.86 (1H, s), 10.10 (1H, s); ESMS m/z 388 (M+H), C₂₂H₁₇N₃O₄=387 g/mol; HPLC purity=91.9%.

5.1.2.76 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N,N-dimethylcarboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, N,N-dimethylamine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ2.72 (3H, s), 6.90 (2H, d, J=8.79 Hz), 6.94 (2H, d, J=8.79 Hz), 7.46 (2H, d, J=8.61 Hz), 7.54 (2H, d, J=8.79 Hz), 10.04 (1H, s), 10.28 (1H, s); ESMS m/z 325 (M+H), C₁₈H₁₆N₂O₄=324 g/mol; HPLC purity=95.6%.

5.1.2.77 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-ethylcarboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, ethylamine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ2.49 (3H, t, J=1.83 Hz), 3.18-3.25 (2H, m), 6.86 (2H, d, J=8.61 Hz), 6.91 (2H, d, J=8.79 Hz), 7.55 (2H, d, J=8.79 Hz), 7.62 (2H, d, J=8.79 Hz), 8.64 (1H, t, J=5.49 Hz), 9.87 (1H, s), 10.10 (1H, s); ESMS m/z 325 (M+H), C₁₈H₁₆N₂O₄=324 g/mol; HPLC purity=95.1%.

5.1.2.78 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-pyrrolidinylethoxy)phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, (2-chloroethyl)pyrrolidine was used for alkylation.

LC/MS m/z 471 (MH+), C₂₈H₂₆N₂O₅=470 g/mol; purity=90%.

5.1.2.79 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-morpholin-4-ylethoxy)phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, 4-(2-chloroethyl)morpholine was used for alkylation.

LC/MS m/z 487 (MH+), C₂₈H₂₆N₂O₆=486 g/mol; purity=90%.

5.1.2.80 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[3-(dimethylamino)propoxy]phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, (3-chloropropyl)dimethylamine was used for alkylation.

LC/MS m/z 459 (MH+), C₂₇H₂₆N₂O₅=458 g/mol; purity=90%.

5.1.2.81 Synthesis of 4-[3-(diethylamino)propoxy]phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, (3-chloropropyl)diethylamine was used for alkylation.

LC/MS m/z 487 (MH+), C₂₉H₃₀N₂O₅=486 g/mol; purity=90%.

5.1.2.82 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-cyclopropylcarboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, cyclopropylamine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ0.04-0.08 (2H, m), 0.34-0.37 (2H, m), 2.48-2.51 (1H m), 6.57 (2H, d, J=8.61 Hz), 6.62 (2H, d, J=8.79 Hz), 7.23 (2H, d, J=8.61 Hz), 7.30 (2H, d, J=8.79 Hz), 8.40-8.41 (1H, m), 9.46 (1H, s), 9.87 (1H, s); ESMS m/z 337 (M+H, C₁₉H₁₆N₂O₄=336 g/mol; HPLC purity=81.1%.

5.1.2.83 Synthesis of [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-cyclobutylcarboxamide

This compound was synthesized as described in Section 5.1.2.69 except, in step 5, cyclobutylamine was used for amide bond formation.

¹H NMR (d₆-DMSO): δ1.59-1.67 (2H, m), 1.78-1.88 (2H, m), 2.15-2.22 (2H, m), 4.31-4.37 (1H, m), 6.85 (2H, d, J=8.59 Hz), 6.90 (2H, d, J=8.77 Hz), 7.54 (2H, d, J=8.59 Hz), 7.60 (2H, d, J=8.77 Hz), 8.88 (1H, d, J=7.59 Hz), 9.87 (1H, s), 10.11 (1H, s); ESMS m/z 351 (M+H), C₂₀H₁₈N₂O₄=350 g/mol; HPLC purity=98.0%.

5.1.2.84 Synthesis of 4-[2-(diethylamino)ethoxy]phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, (2-chloroethyl)diethylamine was used for alkylation.

LC/MS m/z 473 (MH+), C₂₈H₂₈N₂O₅=472 g/mol; purity=90%.

b 5.1.2.85 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(dimethylamino)ethoxy]phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, (2-chloroethyl)dimethylamine was used for alkylation.

LC/MS m/z 445 (MH+), C₂₆H₂₄N₂O₅=444 g/mol; purity=90%.

5.1.2.86 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-{2-[methylbenzylamino]ethoxy}phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, (2-chloroethyl)methylbenzylamine was used for alkylation.

LC/MS m/z 521 (MH+), C₃₂H₂₈N₂O₅=520 g/mol; purity=90%.

5.1.2.87 Synthesis of 2-(4-{[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]carbonyl}phenoxy)-N,N-dimethylacetamide

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, 2-chloro-N,N-dimethylacetamide was used for alkylation.

LC/MS m/z 459 (MH+), C₂₆H₂₂N₂O₆=458 g/mol; purity=90%.

5.1.2.88 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(1-methylpyrrolidin-2-yl)ethoxy]phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, 2-(2-chloroethyl)-1-methylpyrrolidine was used for alkylation.

LC/MS m/z 485 (MH+), C₂₉H₂₈N₂O₅=484 g/mol; purity=90%.

5.1.2.89 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[(1-methyl(3-piperidyl))methoxy]phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, 2-(chloromethyl)-1-methylpiperidine was used for alkylation.

LC/MS m/z 485 (MH+), C₂₉H₂₈N₂O₅=484 g/mol; purity=90%.

5.1.2.90 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[3-(4-methylpiperazinyl)propoxy]phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, 1-(2-chloroethyl)-4-methylpiperazine was used for alkylation.

LC/MS m/z 514 (MH+), C₃₀H₃₁N₃O₅=513 g/mol; purity=90%.

5.1.2.91 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(1-methyl(4-piperidyloxy))phenyl ketone

This compound was synthesized as described in Section 5.1.2.20 except, in step 6, 4-chloro-1-methylpiperidine was used for alkylation.

LC/MS m/z 471 (MH+), C₂₈H₂₆N₂O₅=470 g/mol; purity=90%.

5.1.2.92 Synthesis of 3-ethyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

Synthesis of this compound was performed using the methods described in Scheme 7.

Step 1: Synthesis of 1,3-diketone was following the same procedure as for Step 1 in Section 5.1.2.7 using p-anisyol chloride and 1-(2-bromo-4-methoxyphenyl)butan-1-one as starting materials.

Step 2: Isoxazole formation was following the same procedure as for Step 4 in Section 5.1.2.7 to afford 1-[5-(2-bromo-4-methoxyphenyl)-4-ethylisoxazol-3-yl]-4-methoxybenzene.

Step 3: To a solution of phenylbromoisoxazole (1 eq., obtained from above step) in THF at −78° C. was added nBuLi (1.1 eq., 1.6 M in hexane). After the solution was stirred at −78° C. for 1.5 h, it was added dropwise into a solution of the bromoethane (1.2 eq.) in THF at −78° C. After 15 min., the solution was allowed to warm to room temperature and stirred overnight. After quenching reaction with 1 M HCl, the layers were separated and the aqueous layer extracted with EtOAc (×3). The combined organic layers were washed with saturated NaHCO₃ (×1) and brine, dried over Na₂SO₄, filtered and concentrated to afford a crude product mixture. Flash chromatography yielded the alkylated product.

Step 4: Demethylation was using Method 1 described for Step C of Scheme 1.

¹H NMR (d₆-acetone): δ7.61 (dd, J=1.8, 8.8 Hz, 2H), 7.21 (d, J=8.3 Hz, 1H), 7.00 (dd, J=1.8, 8.8 Hz, 2H), 6.90 (d, J=2.3 Hz, 1H), 6.83 (dd, J=2.3, 8.3 Hz, 1H), 2.55 (q, J=7.4, 2H), 2.54 (q, J=7.4 Hz, 2H), 1.13 (t, J=7.4 Hz, 3H), 0.96 (t, J=7.4 Hz, 3H); LC/MS m/z 310 (MH+), C₁₉H₁₉NO₃=309 g/mol; purity=99%.

5.1.2.93 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-methylphenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, iodomethane was used as the electrophile.

¹H NMR (d₆-acetone): δ7.60 (d, J=8.8 Hz, 2H), 7.22 (d, J=8.8 Hz, 1H), 7.00 (d, J=8.8 Hz, 2H), 6.87 (d, J=2.3 Hz, 1H), 6.82 (dd, J=8.3,2.3 Hz, 1H), 2.55 (q, J=7.4 Hz, 2H), 2.22 (s, 3H), 0.95 (t, J=7.4 Hz, 3H); LC/MS m/z 296 (MH+), C₁₈H₁₇NO₃=295 g/mol; purity=99%.

5.1.2.94 Synthesis of 3-bromo-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized by following the procedures described for Scheme 1 using p-anisyol chloride and 1-(2-bromo-4-methoxyphenyl)butan-1-one as starting materials. Demethylation was using Method 1 described for Step C in Scheme 1.

¹H NMR (d₆-acetone): δ7.60 (d, J=8.8 Hz, 2H), 7.37 (d, J=8.8 Hz, 1H), 7.28 (d, J=2.3 Hz), 7.02-6.99 (m, 3H), 2.56 (q, J=7.4 Hz, 2H), 0.96 (t, J=7.4 Hz, 3H); LC/MS m/z 360 (MH+), C₁₇H₁₄BrNO₃=359 g/mol; purity=99%.

5.1.2.95 Synthesis of 3-butyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

The compound was synthesized as described in Section 5.1.2.92. In step 3, 1-bromobutane was used as the electrophile.

¹H NMR (d₆-acetone): δ7.60 (d, J=8.8 Hz, 2H), 7.21 (d, J=8.3 Hz, 1H), 7.00 (d, J=8.8 Hz, 2H), 6.89 (d, J=2.3 Hz, 1H), 6.83 (dd, J=8.3, 2.3 Hz, 1H), 2.56 (2q, J=7.4 Hz, 4H), 1.53-1.45 (m, 2H), 1.30-1.22 (m, 2H), 0.96 (t, J=7.4 Hz, 3H), 0.84 (t, J=7.4 Hz, 3H); LC/MS m/z 338 (MH+), C₂₁H₂₃NO₃=337 g/mol; purity=99%.

5.1.2.96 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-hexylphenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, 1-bromohexane was used as the electrophile.

¹H NMR (d₆-acetone): δ7.60 (d, J=8.8 Hz, 2H), 7.21 (d, J=8.3 Hz, 1H), 6.99 (d, J=8.8 Hz, 2H), 6.90 (d, J=2.3 Hz, 1H), 6.82 (dd, J=8.3,2.3 Hz, 1H), 2.56 (2q, J=7.4 Hz, 4H), 1.52-1.46 (m, 2H), 1.29-1.22 (m, 6H), 0.96 (t, J=7.4 Hz, 3H), 0.83 (t, J=6.4 Hz, 3H); LC/MS m/z 366 (MH+), C₂₃H₂₇NO₃=365 g/mol; purity=99%.

5.1.2.97 Synthesis of 3-(2-bromopropyl)-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, 3-bromo-1-propene was used as the electrophile.

¹H NMR (d₆-acetone): δ7.61 (d, J=8.8 Hz, 2H), 7.28 (d, J=8.3, 1H), 7.02-6.99 (m, 3H), 6.92 (dd, J=8.3, 2.7 Hz, 1H), 4.31-4.27 (m, 1H), 3.14 (d, J=6.9, 2H), 2.58 (q, J=7.8 Hz, 2H), 1.62 (d, J=6.5 Hz, 3H), 0.98 (t, J=7.8 Hz, 3H); LC/MS m/z 402 (MH+), C₂₀H₂₀BrNO₃=401 g/mol; purity=96%.

5.1.2.98 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazole-4-carbaldehyde

This compound was synthesized based upon Scheme 7.

Step 1-4: Same as corresponding steps in Section 5.1.2.20.

Step 5: Weinreb amide formation. 4-carboxy isoxazole (obtained from Steps 1-4 above) was dissolved in THF and activated with EDC:HOBt:DIEA (1.5:1.5:1.5) and allowed to stand at rt for 5 min. N-methoxymethylamine (1.5 equiv.) was then added. The reaction mixture was allowed to stand at rt overnight, after which it was diluted with EtOAc and washed with 10% citric acid, 10% NaHCO₃, and brine. The solvent was removed, and the residue was purified by flash chromatography (EtOAc/petrol) and lyophilized in 90% MeCN/H₂O to give the desired product as a white powder.

Step 6: Reduction of the amide to aldehyde. The Weinreb amide (obtained from step 5) was dissolved in THF and added to a suspension of LiAlH₄ (4 equiv.) in THF at −78° C. The reaction was allowed to stir at −78° C. for 2.5 h and was quenched by dropwise addition of 1M HCl. The reaction mixture was then diluted with EtOAc and washed with 10% NaHCO₃ and brine. After drying over Na₂SO₄, the solvent was removed and the residue was lyophilized in 90% MeCN/H₂O.

Step 7: Demethylation was performed based upon Method 3 described for step C in Scheme 1. The above aldehyde was dissolved in DCM and cooled in an ice-bath. BBr₃ (10 equiv.) was added and the reaction was allowed to stir at rt for 5 h. The reaction was then cooled in an ice-bath and quenched with water. EtOAc was added and the reaction was washed with water and brine. After drying over Na₂SO₄, the solvent was removed and the residue was purified by flash chromatography (EtOAc/petrol) to yield pure product.

¹H NMR (d₆-DMSO): δ6.85 (2 h, d, J=8.42 Hz), 6.93 (2H, d, J=8.61 Hz), 7.54 (2H, d, J=8.42 Hz), 7.88 (2H, d, J=8.61 Hz), 9.81 (1H, s); ESMS m/z 282 (M+H), C₁₆H₁₁NO₄=281 g/mol; HPLC purity=97.1%.

5.1.2.99 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-iodophenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, iodine was used as the electrophile.

¹H NMR (d₆-acetone): δ7.61 (d, J=8.8 Hz, 2H), 7.54 (d, J=2.3 Hz, 1H), 7.31 (d, J=8.3 Hz, 1H), 7.05 (dd, J=8.3, 2.3 Hz, 1H), 7.00 (d, J=8.8 Hz, 2H), 2.54 (q, J=7.4 Hz, 2H), 0.98 (t, J=7.4 Hz, 3H); LC/MS m/z 408 (MH+), C₁₇H₁₄INO₃=407 g/mol; purity=99%.

5.1.2.100 Synthesis of 3-chloro-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, NCS was used as the electrophile.

¹H NMR (d₆-acetone): δ7.60 (d, J=8.8 Hz, 2H), 7.39 (d, J=8.8 Hz, 1H), 7.10 (d, J=2.8 Hz, 1H), 7.05-6.98 (m, 3H), 2.57 (q, J=7.8 Hz, 2H), 0.96 (t, J=7.4 Hz, 3H); LC/MS m/z 316 (MH+), C₁₇H₁₄ClNO₃=315 g/mol; purity=99%.

5.1.2.101 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-fluorophenol

This compound was synthesized by following Scheme 1 using p-anisyol chloride and 1-(3-fluoro-4-methoxyphenyl)butan-1-one as starting materials. Demethylation was using Method 1 described for Step C Scheme 1.

¹H NMR (d₆-acetone): δ; LC/MS m/z 300 (MH+), C₁₇H₁₄FNO₃=299 g/mol; purity=95%.

5.1.2.102 Synthesis of 2-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-5-hydroxybenzoic acid

The compound was synthesized as described in Section 5.1.2.92. In Step 3, ethyl chloroformate was used as the electrophile.

¹H NMR (d₆-acetone): δ7.60-7.54 (m, 3H), 7.38 (s, 1H), 7.20 (d, J=8.3 Hz, 1H), 6.99 (d, J=8.8 Hz, 2H), 2.56 (d, J=7.8 Hz, 2H), 0.97 (t, J=7.4 Hz, 3H); LC/MS m/z 326 (MH+), C₁₈H₁₅NO₅=325 g/mol; purity=99%.

5.1.2.103 Synthesis of ethyl 2-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-5-hydroxybenzoate

The compound was synthesized as described in Section 5.1.2.92. In Step 3, ethyl chloroformate was used as the electrophile. Demethylation was following Method 3 described for Step C in Scheme 1.

¹H NMR (d₆-acetone): δ7.64 (d, J=8.8 Hz, 2H), 7.49 (d, J=2.8 Hz, 1H), 7.34 (d, J=8.3 Hz, 1H), 7.19 (dd, J=8.3, 2.3 Hz, 1H), 7.01 (d, J=8.8 Hz, 2H), 4.12 (q, J=7.4 Hz, 2H), 2.54 (q, J=7.4 Hz, 2H), 1.08 (t, J=7.4 Hz, 3H), 0.98 (t, J=7.4 Hz, 3H); LC/MS m/z 354 (MH+), C₂₀H₁₉NO₅=353 g/mol; purity=99%.

5.1.2.104 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-(methylsulfinyl)phenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, methyl disulfide was used as the electrophile.

¹H NMR (d₆-acetone): δ7.66 (d, J=2.3 Hz, 1H), 7.60 (d, J=8.8 Hz, 2H), 7.50 (d, J=8.3 Hz, 1H), 7.15 (dd, J=8.3, 2.3 Hz, 1H), 7.01 (d, J=8.8 Hz, 2H), 2.83 (s, 3H), 2.64 (q, J=7.4 Hz, 2H), 1.00 (t, J=7.4 Hz, 3H); LC/MS m/z 344 (MH+), C₁₈H₁₇NO₄S=343 g/mol; purity=99%.

5.1.2.105 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-sulfanylphenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, methyl disulfide was used as the electrophile. Demethylation was following Method 3 described for Step C in Scheme 1.

¹H NMR (d₆-acetone): δ7.68 (d, J=2.3 Hz, 1H), 7.60 (d, J=8.8 Hz, 2H), 7.50 (d, J=8.3 Hz, 1H), 7.15 (dd, J=8.3, 2.3 Hz, 1H), 7.01 (d, J=8.8 Hz, 2H), 2.65 (q, J=7.4 Hz, 2H), 1.00 (t, J=7.4 Hz, 3H); LC/MS m/z 314 (MH+), C₁₇H₁₅NO₃S=313 g/mol; purity=87%.

5.1.2.106 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-methylphenol

The compound was synthesized as described in Section 5.1.2.92. In Step 1, p-anisyol chloride and 1-(3-bromo-4-methoxyphenyl)butan-1-one as starting materials. In Step 3, iodomethane was used as the electrophile.

¹H NMR (d₆-acetone): δ7.63 (d, J=8.8 Hz, 2H), 7.54 (d, J=8 Hz, 1H), 7.42 (s, 1H), 7.04-6.96 (m, 3H), 2.74 (q, J=7.4 Hz, 2H), 2.29, 2.28 (2s, 3H), 1.11 (t, J=7.4 Hz, 3H); LC/MS m/z 296 (MH+), C₁₈H₁₇NO₃=295 g/mol; purity=98%.

5.1.2.107 Synthesis of 2-butyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

The compound was synthesized as described in Section 5.1.2.106. In Step 3, 1-bromobutane was used as the electrophile.

¹H NMR (d₆-acetone): δ7.64 (d, J=8.8 Hz, 1H), 7.54 (d, J=8.8 Hz, 2H), 7.43 (s, 1H), 7.04-6.98 (m, 3H), 2.74 (q, J=7.4 Hz, 2H), 2.72 (t, J=7.4 Hz, 2H), 1.69-1.61 (m, 2H), 1.45-1.38 (m, 2H), 1.12 (t, J=7.4 Hz, 3H), 0.95 (t, J=7.4 Hz, 3H); LC/MS m/z 338 (MH+), C₂₁H₂₃NO₃=337 g/mol; purity=99%.

5.1.2.108 Synthesis of 2-ethyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

The compound was synthesized as described in Section 5.1.2.106. In Step 3, bromoethane was used as the electrophile.

¹H NMR (d₆-acetone): δ7.64 (d, J=8.8 Hz, 2H), 7.54 (d, J=8.8 Hz, 1H), 7.44 (d, J=2.3 Hz, 1H), 7.01-6.97 (m, 3H), 2.75 (q, J=7.4 Hz, 2H), 2.73 (q, J=7.4 Hz, 2H), 1.24 (t, J=7.4 Hz, 3H), 1.13 (t, J=7.4 Hz, 3H); LC/MS m/z 310 (MH+), C₁₉H₁₉NO₃=309 g/mol; purity=99%.

5.1.2.109 Synthesis of 2-bromo-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

This compound was synthesized by following Scheme 1 using p-anisyol chloride and 1-(3-bromo-4-methoxyphenyl)butan-1-one as starting materials. Demethylation was performed using Method 1 described for Step C in Scheme 1.

¹H NMR (d₆-acetone): δ7.89 (d, J=2.3 Hz, 1H), 7.64 (d, J=9.2 Hz, 1H), 7.54 (d, J=8.8 Hz, 2H), 7.20 (dd, J=1.4, 8.3 Hz, 1H), 7.02 (dd, J=0.9, 8.8 Hz, 2H), 2.75 (q, J=7.5 Hz, 2H), 1.12 (t, J=7.9, 3H); LC/MS m/z 360 (MH+), C₁₇H₁₄BrNO₃=359 g/mol; purity=99%.

5.1.2.110 Synthesis of 4-[3-(4-butanoyloxyphenyl)-4-ethylisoxazol-5-yl]phenyl butanoate

This compound was made as a derivative of the compound prepared according to Section 5.1.2.4. To a THF solution of 4-[4-ethyl-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol was added butyryl chloride (3.0 eq.) and pyridine (3.0 e.q.). The mixture was stirred at rt for 24 h, poured into cold NaHCO₃, extracted with EtOAc. The organic extracts were washed with brine, dried with Na₂SO₄ and concentrated in vacuo to give the product as a white powder.

LC/MS m/z 422 (MH+), C₂₅H₂₇NO₅=421 g/mol; purity=98%.

5.1.2.111 Synthesis of 4-[3-(4-acetyloxyphenyl)-4-ethylisoxazol-5-yl]phenyl acetate

This compound was made as a derivative of the compound prepared according to Section 5.1.2.4. To a THF solution of 4-[4-ethyl-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol was added acetyl chloride (3.0 eq.) and pyridine (3.0 eq). The mixture was stirred at rt for 24 h, poured into cold NaHCO₃, extracted with EtOAc. The organic extracts were washed with brine, dried with Na₂SO₄ and concentrated in vacuo to give the product as a white powder.

LC/MS m/z 366 (MH+), C₂₁H₁₉NO₅=365 g/mol; purity=98%.

5.1.2.112 Synthesis of 3-(4-butanoyloxyphenyl)naphtho[1,2-c]isoxazol-7-yl butanoate

This compound was made as a derivative of the compound prepared as described in Section 5.1.2.32. To a THF solution of 3-(4-hydroxyphenyl)naphtho[1,2-c]isoxazol-7-ol was added butyryl chloride (3.0 eq.) and pyridine (3.0 eq.). The mixture was stirred at rt for 24 h, poured into cold NaHCO₃, extracted with EtOAc. The organic extracts were washed with brine, dried with Na₂SO₄ and concentrated in vacuo to give the product as a white powder.

LC/MS m/z 418 (MH+), C₂₅H₂₃NO₅=417 g/mol; purity=98%.

5.1.2.113 Synthesis of 3-(4-acetyloxyphenyl)naphtho[1,2-c]isoxazol-7-yl acetate

This compound was made as a derivative of the compound prepared as described in Section 5.1.2.32. To a THF solution of 3-(4-hydroxyphenyl)naphtho[1,2-c]isoxazol-7-ol was added acetyl chloride (3.0 eq.) and pyridine (3.0 eq.). The mixture was stirred at rt for 24 h, poured into cold NaHCO₃, extracted with EtOAc. The organic extracts were washed with brine, dried with Na₂SO₄ and concentrated in vacuo to give the product as a white powder.

LC/MS m/z 362 (MH+), C₂₁H₁₅NO₅=361 g/mol; purity=98%.

5.1.2.114 Synthesis of 3,5-bis(4-methoxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone, chloride

This compound was synthesized by following the methods outlined in Scheme 5.

Steps 1-6 were performed as described in Section 5.1.2.20.

Step 7: Formation of HCl salt. The pure product obtained from Step 6 was dissolved in acetone. To this solution was added at least 5 eq. of conc. HCl aq. and an acetonitrile/H2O (1:1) solution. The mixture was then lyophilized overnight to give the product as an off-white powder.

LC/MS m/z 360 (MH+), C₁₇H₁₄BrNO₃=359 g/mol; purity=99%.

5.1.2.115 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-hexylphenol

The compound was synthesized as described in Section 5.1.2.106. In Step 3, 1-bromohexane was used as the electrophile.

¹H NMR (d₆-acetone): δ7.63 (d, J=8.8 Hz, 2H), 7.53 (d, J=8.8 Hz, 1H), 7.43 (d, J=2.3 Hz, 1H), 7.04-7.97 (m, 3H), 2.76-2.68 (m, 4H), 1.74-1.62 (m, 2H), 1.36-1.33 (m, 6H), 1.12 (t, J=7.8 Hz, 3H), 0.91 (t, J=7.4 Hz, 3H); LC/MS m/z 366 (MH+), C₂₃H₂₇NO₃=365 g/mol; purity=99%.

5.1.2.116 Synthesis of 2-chloro-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol

The compound was synthesized as described in Section 5.1.2.106. In step 3, NCS was used as the electrophile.

¹H NMR (d₆-acetone): δ7.67-7.50 (m, 4H), 7.20 (d, J=8.3 Hz, 1H), 7.03 (d, J=8.8 Hz, 2H), 2.76 (q, J=7.4 Hz, 2H), 1.13 (t, J=7.4 Hz, 3H); LC/MS m/z 315 (MH+), C₁₇H₁₄ClNO₃=314 g/mol; purity=95%.

5.1.2.117 Synthesis of 5-[4-ethyl-5-(4-hydroxyphenyl)isoxazol-3-yl]pyridin-2-ol

This compound was synthesized by following Scheme 1, using p-anisyol chloride and methyl 6-methoxypyridine-3-carboxylate as starting materials. Demethylation was using Method 1 described for Step C in Scheme 1.

¹H NMR (d₆-DMSO) δ10.04 (one isomer: s, 1H), 9.87 (other isomer: s, 1H), 7.78-6.47 (m, 7H), 2.64 (q, J=7.50 Hz, 2H), 1.08 (one isomer: t, J=7.50 Hz, 3H), 1.02(other isomer: t, J=7.50 Hz, 3H); LC/MS m/z 283 (MH+), C₁₆H₁₄N₂O₃=282 g/mol; purity=99%.

5.1.2.118 Synthesis of ethyl 5-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-hydroxybenzoate

The compound was synthesized as described in Section 5.1.2.106. In Step 3, chloro ethylformate was used as the electrophile. Demethylation was following Method 3 described for Step C in Scheme 1.

¹H NMR (d₆-acetone): δ7.89 (d, J=8.8 Hz, 1H), 7.65 (d, J=8.8 Hz, 2H), 7.55 (d, J=8.8 Hz, 1H), 7.17 (d, J=8.8 Hz, 1H), 7.04 (d, J=8.8 Hz, 2H), 4.48 (q, J=7.1 Hz, 2H), 2.76 (q, J=7.4 Hz, 2H), 1.44 (t, J=7.6 Hz, 3H), 1.16 (t, J=7.6 Hz, 3H); LC/MS m/z 354 (MH+), C₂₀H₁₈NO₅=353 g/mol; purity=91%.

5.1.2.119 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-methylphenyl ketone

This compound was synthesized by following the procedure described in Scheme 7.

Steps, 1-3, were performed as described in Section 5.1.2.20.

Step 4: Again, this step was performed as described in Step 4 of Section 5.1.2.20 except p-toluoyl chloride was used for acylation.

Step 5: Demethylation was following Method 3 described for Step C in Scheme 1.

¹H NMR (d₆-DMSO): δ2.26 (3H, s), 6.70 (2H, d, J=8.8 Hz), 6.76 (2H, d, J=9.0 Hz), 7.19 (2H, d, J=8.0 Hz), 7.26 (2H, d J=8.8 Hz), 7.39 (2H, d, J=9.0 Hz), 7.63 (2H, d, J=8.2 Hz), 9.92 (1H, s,br); ESMS m/z 372 (M+H), C₂₃H₁₇NO₄=371 g/mol; HPLC purity=98%.

5.1.2.120 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 2-chlorophenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, o-chlorobenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.67 (2H, d, J=8.8 Hz), 6.75 (2H, d, J=8.8 Hz), 7.18 (1H, ddd, J=7.8, 7.2, 1.3 Hz), 7.24-7.27 (1H, m), 7.24 (2H, d, J=8.8 Hz), 7.31 (1H, ddd, J=7.8, 7.2, 1.8 Hz), 7.46 (1H, dd, J=7.8, 1.3 Hz), 7.51 (2H, d, J=9.0 Hz), 9.77 (1H, s,br); ESMS m/z 392 (M+H), C₂₂H₁₄ClNO₄=391 g/mol; HPLC purity=97%.

5.1.2.121 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-chlorophenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, m-chlorobenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.71 (2H, d, J=8.8 Hz), 6.77 (2H, d, J=8.6 Hz), 7.25 (2H, d, J=8.8 Hz), 7.35 (1H, t, J=7.8 Hz), 9.81 (1H, 7.43 (2H, d, J=8.8 Hz), 7.57 (1H, ddd, J=8.0, 2.2, 1.0 Hz), 7.61 (1H, dt, J7.8, 1.2 Hz), 7.70 (1H, t, J=1.8 Hz), 9.81 (1H, s), 10.14 (1H, s); ESMS m/z 392 (M+H), C₂₂H₁₄ClNO₄=391 g/mol; HPLC purity=86%.

5.1.2.122 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-chlorophenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Sep 4, p-chlorobenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.71 (2H, d, J=8.8 Hz), 6.77 (2H, d, J=8.8 Hz), 7.25 (2H, d, J=8.8 Hz), 7.41 (2H, d, J=8.8 Hz), 7.42 (2H, d, J=8.8 Hz), 7.72 (2H, d, J=8.8 Hz), 9.82 (1H, s), 10.14 (1H, s); ESMS m/z 392 (M+H), C₂₂H₁₄ClNO₄=391 g/mol; HPLC purity=90%.

5.1.2.123 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 2-fluorophenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, o-fluorobenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.68 (2H, d, J=8.8 Hz), 6.77 (2H, d, J=9.0 Hz), 7.01 (1H, dd, J=11.1, 8.2 Hz), 7.13 (1H, td, J=7.8, 1.0 Hz), 7.25 (2H, d, J=8.8 Hz), 7.42-7.48 (1H, m), 7.51 (2H, d, J=8.8 Hz), 7.59 (1H, td, J=6.8, 1.8 Hz), 9.89 (1H, s,br); ESMS m/z 376 (M+H), C₂₂H₁₄FNO₄=375 g/mol; HPLC purity=98%.

5.1.2.124 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-nitrophenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, m-nitrobenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.68 (2H, d, J=8.4 Hz), 6.75 (2H, d, J=8.8 Hz), 7.26 (2H, d, J=8.4 Hz), 7.47 (2H, d, J=8.6 Hz), 7.59 (1H, t, J=8.0 Hz), 8.06 (1H, dd, J=7.8, 1.2 Hz), 8.29 (1H, dd, J=8.2, 2.3 Hz), 8.36 (1H, t=2.0 Hz), 9.89 (1H, s,br);

ESMS m/z 403 (M+H), C₂₂H₁₄N₂O₆=402 g/mol; HPLC purity=95%.

5.1.2.125 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-nitrophenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, p-nitrobenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.70 (2H, d, J=8.8 Hz), 6.76 (2H, d, J=8.8 Hz), 7.25 (2H, d, J=8.8 Hz), 7.44 (2H, d, J=8.8 Hz), 7.93 (2H, d, J=9.0 Hz), 8.11 (2H, d, J=8.8 Hz), 9.90 (1H, s,br); ESMS m/z 403 (M+H), C₂₂H₁₄N₂O₆=402 g/mol; HPLC purity=93%.

5.1.2.126 Synthesis of 3,4-dichlorophenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, 3,4-dichloro-benzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.71 (2H, d, J=8.8 Hz), 6.78 (2H, d, J=9.0 Hz), 7.25 (2H, d, J=8.8 Hz), 7.44 (2H, d, J=8.8 Hz), 7.58 (1H, d, J=8.4 Hz), 7.62 (1H, dd, J=8.4, 2.0 Hz), 7.88 (1H, d, J=2.0 Hz), 9.82 (1H, s), 10.16 (1H, s); ESMS m/z 426 (M+H), C₂₂H₁₃Cl₂NO₄=425 g/mol; HPLC purity=96%.

5.1.2.127 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-butylphenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, p-n-butylbenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ0.80 (3H, t, J=7.4 Hz), 1.16-1.24 (2H, m), 1.40-1.50 (2H, m), 2.53 (2H, t, J=7.6 Hz), 6.70 (2H, d, J=8.8 Hz), 6.75 (2H, d, J=9.0 Hz), 7.19 (2H, d, J=8.6 Hz), 7.26 (2H, d, J=8.8 Hz), 7.39 (2H, d, J=8.8 Hz), 7.63 (2H, d, J=8.4 Hz); ESMS m/z 414 (M+H), C₂₆H₂₃NO₄=413 g/mol; HPLC purity=92%.

5.1.2.128 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(tert-butyl)phenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, p-t-butylbenzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ1.18 (9H, s), 6.71 (2H, d, J=8.8 Hz), 6.76 (2H, d, J=8.8 Hz), 7.28 (2H, d, J=8.8 Hz), 7.39 (2H, d, J=9.0 Hz), 7.40 (2H, d, J=8.8 Hz), 7.66 (2H, d, J=8.6 Hz), 9.81 (1H, s), 10.10 (1H, s); ESMS m/z 414 (M+H), C₂₆H₂₃NO₄=413 g/mol; HPLC purity=98%.

5.1.2.129 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-hydroxyphenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, m-anisoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.68-6.72 (1H, m), 6.71 (1H, d, J=8.8 Hz), 6.77 (2H, d, J=8.8 Hz), 6.83 (1H, dd, J=8.2, 0.6 Hz), 7.27 (2H, d, J=8.8 Hz), 7.34-7.40 (2H, m), 7.43 (2H, d, J=8.8 Hz), 9.80 (1H, s), 10.11 (1H, s), 11.00 (1H, s); ESMS m/z 374 (M+H), C₂₂H₁₅NO₅=373 g/mol; HPLC purity=95%.

5.1.2.130 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 2-hydroxyphenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, o-anisoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.71 (2H, d, J=8.8 Hz), 6.77 (2H, d, J=8.8 Hz), 6.93 (1H, ddd, J=7.6, 2.6, 1.6 Hz), 7.11-7.19 (3H, m), 7.27 (2H, d, J=8.8Hz), 7.39 (2H, d, J=8.8 Hz), 9.75 (1H, s), 9.83 (1H, s), 10.13 (1H, s); ESMS m/z 374 (M+H), C₂₂H₁₅NO₅=373 g/mol; HPLC purity=96%.

5.1.2.131 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl phenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, benzoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ6.69 (2H, d, J=8.8 Hz), 6.75 (2H, d, J=8.8 Hz), 7.26 (2H, d, J=8.8 Hz), 7.40 (2H, d, J=8.8 Hz), 7.53 (1H, t, J=7.5 Hz), 7.72 (2H, dd, J=8.3, 1.2 Hz), 9.80 (1H, s), 10.11 (1H, s); ESMS m/z 358 (M+H), C₂₂H₁₅NO₄=357 g/mol; HPLC purity=93%.

5.1.2.132 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-methoxyphenyl ketone

This compound was synthesized as described in Section 5.1.2.119. In Step 4, p-anisoyl chloride was used for acylation.

¹H NMR (d₆-DMSO): δ3.77 (3H, s), 6.71 (2H, d, J=9.0 Hz), 6.77 (2H, d, J=9.0 Hz), 6.91 (2H, d, J=8.8 Hz), 7.28 (2H, d, J=9.0 Hz), 7.39 (2H, d, J=9.0 Hz), 7.72 (2H, d, J=9.0 Hz), 9.80 (1H, s), 10.12 (1H, s); ESMS m/z 388 (M+H), C₂₃H₁₇NO₅=387 g/mol; HPLC purity=97%.

5.1.2.133 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-phenylthiophenol

The compound was synthesized as described in Section 5.1.2.92. In Step 3, phenyl disulfide was used as the electrophile.

¹H NMR (d₆-acetone): δ7.58 (d, J=8.8 Hz, 2H), 7.42-7.38 (m, 5H), 7.32 (d, J=8.3 Hz, 1H), 6.99 (d, J=8.8 Hz, 2H), 6.87 (dd, J=2.8, 8.5 Hz, 1H), 6.68 (d, J=2.3 Hz, 1H), 2.56 (q, J=7.4 Hz, 2H), 0.97 (t, J=7.4 Hz, 3H); LC/MS m/z 390 (MH+), C₂₃H₁₉NO₃S=389 g/mol; purity=95%.

5.1.2.134 Synthesis of 5-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-hydroxybenzamide

The compound was synthesized as described in Section 5.1.2.106. In Step 3, tosyl nitrile was used as the electrophile.

¹H NMR (d₆-acetone): δ7.71 (dd, J=2.3, 8.3 Hz, 1H), 7.64 (d, J=8.8 Hz, 2H), 7.54 (d, J=2.3 Hz, 1H), 7.07-6.99 (m, 3H), 2.76 (q, J=7.4 Hz, 2H), 1.09 (t, J=7.4 Hz, 3H); LC/MS m/z 325 (MH+), C₁₈H₁₆N₂O₄=324 g/mol; purity=99%.

5.1.2.135 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-phenylthiophenol

The compound was synthesized as described in Section 5.1.2.106. In Step 3, phenyl disulfide was used as the electrophile.

¹H NMR (d₆-acetone): δ7.59-7.36 (m, 9H), 7.14 (d, J=8.3 Hz, 1H), 7.01 (d, J=8.8 Hz, 2H), 2.63 (q, J=7.4 Hz, 2H), 1.02 (t, J=7.4 Hz, 3H); LC/MS m/z 390 (MH+), C₂₃H₁₉NO₃S=389 g/mol; purity=99%.

5.1.2.136 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-methylthiophenol

The compound was synthesized as described in Section 5.1.2.106. In Step 3, methyl disulfide was used as the electrophile.

¹H NMR (d₆-acetone): δ7.64 (d, J=8.8 Hz, 1), 7.54 (d, J=8.8 Hz, 2H), 7.37 (d, J=2.3 Hz, 1H), 7.07-6.99 (m, 3H), 2.76 (q, J=7.4 Hz, 2H), 2.50, 2.47 (2s, 3H), 1.14 (t, J=7.4 Hz, 3H); LC/MS m/z 328 (MH+), C₁₈H₁₇NO₃S=327 g/mol; purity=99%.

5.1.2.137 Synthesis of 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-phenylphenol

The compound was synthesized as described in Section 5.1.2.92.

Steps 1 and 2 were performed as described in Section 5.1.2.92.

Step 3: Suzuki coupling was used to introduce the phenyl ring. The isoxazole obtained from Step 2 was dissolved in toluene and degassed with argon for 10 mim. To this solution was added Pd(PPh₃)₄ (4.0 mol %). After an additional 10 mim, Na₂CO₃ (5 eq.) was added followed by a solution of phenyl boronic acid (1.1 rq.) in ethanol. The reaction was heated to reflux and stirred for 16 h. The reaction mixture was then poured into a separatory funnel and the aqueous layer extracted twice with ethyl acetate. The organic layers were combined, washed with a brine solution and dried over Na₂SO₄. Purification by flash chromatography (40% ethyl acetate/hexanes) yielded the product.

Step 4 Demethylation of the product of Step 3 was performed as described in Method 3 of Step C in Scheme 1.

¹H NMR (d₆-acetone): δ6 7.45-7.40 (m, 3H), 7.32-7.25 (m, 5H), 7.03-7.01 (m, 2H), 6.93 (d, J=7.8 Hz, 2H), 2.15 (q, J=7.4 Hz, 2H), 0.63 (t, J=7.4 Hz, 3H); LC/MS m/z 358 (MH+), C₂₃H₁₉NO₃=357 g/mol; purity=99%.

5.1.2.138 Synthesis of {4-[4-ethyl-3(4-hydroxyphenyl)isoxazol-5-yl]phenyl}(methylsulfonyl)amine

This compound was synthesized by following the procedures described here.

Step 1: Synthesis of 1,3-diketone. This was performed as described in Step 1 of Section 5.1.2.7 except 4′-methoxybutyrylphenone and methyl 4-nitrobenzoyl chloride were used as the starting materials.

Step 2: Isoxazole formation using the above diketone was performed as described as Step 4 of Section 5.1.2.7.

Step 3: Reduction of nitro group to aniline was achieved by Pd-catalyzed hydrogenation. To a solution of product obtained from Step 2 in ethanol was added catalytic amount 10% Pd on charcoal. This mixture was stirred under hydrogen (balloon) overnight, filtered through celite and washed with ethyl acetate. The filtrate was concentrated in vacuo. The residue was purified by flash column chromatography to afford product 4-[4-ethyl-3-(4-methoxyphenyl)isoxazol-5-yl]phenylamine.

Step 4: To a DCM solution of the above aniline was added methanesulfonyl chloride (2.0 eq.) and pyridine (3.0 eq.). The mixture was stirred at rt for 4 h, poured into water and extracted with ethyl acetate. The organic layers were combined, washed with brine and dried over Na₂SO₄. Purification by flash chromatography yielded the product {4-[4-ethyl-3-(4-methoxyphenyl)isoxazol-5-yl]phenyl}(methylsulfonyl)amine.

Step 5: Demethylation was following Method 2 described for Step C in Scheme 1.

¹H NMR (CDCl₃): δ7.74-7.50 (m, 4H), 7.32-7.15 (m, 2H), 6.95-6.88 (m, 2H), 3.06 (m, 3H), 2.68 (m, 2H), 1.14 (m, 3H); LC/MS m/z 359 (MH+), C₁₈H₁₈N₂O₄S=358 g/mol; purity=99%.

5.1.2.139 Synthesis of 5-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-methoxybenzamide

This compound was synthesized as described in Section 5.1.2.134. Partial demethylation of the product afforded 5-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-methoxybenzamide by following the progress of the reaction using thin-layer chromatography.

¹H NMR (d₆-acetone): δ8.42 (d, J=2.3 Hz, 1H), 7.84 (dd, J=8.8, 2.9 Hz, 1H), 7.65 (d, J=8.8 Hz, 2H), 7.36 (d, J=8.8 Hz, 1H), 7.04 (d, J=8.8 Hz, 2H), 4.12, 4.11 (2s, 3H), 2.77 (q, J=7.4 Hz, 3H), 1.15 (t, J=7.4 Hz, 3H); LC/MS m/z 339 (MH+), C₁₉H₁₈N₂O₄=338 g/mol; purity=99%.

5.1.2.140 Synthesis of 5-[4-ethyl-3(4-methoxyphenyl)isoxazol-5-yl]-2-hydroxybenzamide

This compound is the regioisomer of the compound prepared as described in Section 5.1.2.139. Both regioisomers were obtained using the methods described in that Section and the two regioisomers were separated by HPLC using a C₁₈ column (Reliasil-BDXC 18, 10×50 mm, Ranin Dynamax) running a first buffer of H₂O/0.1% TFA and a second buffer of HCN/0.1% TFA through a gradient from 5-95% of the second buffer over a nine-minute period at a flow rate of ten ml/min.

¹H NMR (d₆-acetone): δ8.06 (s, 1H), 7.65 (d, J=8.8 Hz, 1H), 7.55 (d, J=8.8 Hz, 2H), 7.45 (d, J=8.8 Hz, 1H), 7.01 (d, J=8.8 Hz, 2H), 4.08, 4.07 (2s, 3H), 2.78 (q, J=7.4 Hz, 2H), 1.12 (t, J=7.4 Hz, 3H); LC/MS m/z 399 (MH+), C₁₉H₁₈N₂O₄=338 g/mol; purity=99%.

b 5.1.2.141 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol4-yl 3-(2-piperidylethoxy)phenyl ketone, chloride

This compound was synthesized as described in Section 5.1.2.20. In Step 4, 3-allyloxybenzoyl chloride for acylation.

¹H NMR (d₆-DMSO): δ10.28 (s, 1H), 9.96 (s, 1H), 7.46 (d, J=8.76 Hz, 2H), 7.36-7.30 (m, 5H), 7.24-7.20 (m, 1H), 6.84 (d, J=8.76 Hz, 2H), 6.78 (d, J=8.76 Hz, 2H), 4.40-4.30 (br, 2H), 3.50-3.40 (m 4H), 3.00-2.90 (m, 2H), 1.85-1.65 (m, 6H); LC/MS m/z 485 (MH+), C₂₉H₂₈N₂O₅=484 g/mol; purity=95%.

5.1.2.142 Synthesis of 5-(4-hydroxyphenyl)-3-(4-methoxyphenyl)isoxazol-4-yl 3-(2-piperidylethoxy)phenyl ketone, chloride

This compound was synthesized as described in Section 5.1.2.142. Partial demethylation afforded the mono-demethylated product by monitoring reaction progress by thin-layer chromatography.

¹H NMR (d₆-DMSO): δ7.58 (one isomer: d, J=8.76 Hz, 2H), 7.48-7.42 (other isomer: m, 2H), 7.40-7.28 (m, 5H), 7.28-7.18 (m, 1H), 7.03 (one isomer: d, J=8.76 Hz, 2H), 6.97 (other isomer: d, J=8.76 Hz, 2H), 6.83 (other isomer: d, J=8.76 Hz, 2H), 6.78 (other isomer: d, J=8.76 Hz, 2H), 4.40-4.30 (br, 2H), 3.78 one isomer: s, 2H), 3.75 (other isomer: s 1H), 3.50-3.40 (br, 4H), 3.00-2.90 (m, 2H), 1.85-1.65 (m, 6H); LC/MS m/z 499 (MH+), C₃₀H₃₀N₂O₅=498 g/mol; purity=95%.

5.1.2.143 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-(2-pyrrolidinylethoxy)phenyl ketone, chloride

This compound was synthesized as described in Section 5.1.2.141. In Step 6, N-(2-chloroethyl)pyrrolidine was used for alkylation.

¹H NMR (d₆-DMSO): δ10.29 (s, 1H), 9.97 (s, 1H), 7.46 (d, J=8.76 Hz, 2H), 7.36-7.30 (m, 5H), 7.25-7.20 (m, 1H), 6.84 (d, J=8.76 Hz, 2H), 6.78 (d, J=8.76 Hz, 2H), 4.31 (br, 2H), 3.60-3.45 (m 4H), 3.15-3.00 (m 2H), 2.10-1.80 (m, 4H); LC/MS m/z 471 (MH+), C₂₈H₂₆N₂O₅=470 g/mol; purity=99%.

5.1.2.144 Synthesis of 3-[2-(diethylamino)ethoxy]phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone, chloride

This compound was synthesized as described in Section 5.1.2.141. In Step 6, N-(2-chloroethyl)diethylamine was used for alkylation.

¹H NMR (d₆-DMSO): δ10.31 (s, 1H), 9.98 (s, 1H), 7.46 (d, J=8.76 Hz, 2H), 7.36-7.30 (m, 5H), 7.24-7.20 (m, 1H), 6.84 (d, J=8.76 Hz, 2H), 6.78 (d, J=8.76 Hz, 2H), 4.33 (br t, 2H,), 3.4 (m 2H), 3.19-3.14 (m, 4H), 1.25-1.20 (t, J=7.14 Hz, 6H); LC/MS m/z 473 (MH+), C₂₈H₂₈N₂O₅=472 g/mol; purity=99%.

5.1.2.145 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-[(1-methyl(3-piperidyl))methoxy]phenyl ketone, chloride

This compound was synthesized as described in Section 5.1.2.141. In Step 6, 2-(chloromethyl-1-methyl-piperidine was used for alkylation.

¹H NMR (d₆-DMSO): δ10.31 (s, 1H), 9.98 (s, 1H), 7.45 (d, J=8.76 Hz, 2H), 7.33-7.29 (m, 5H), 7.20-7.12 (m, 1H), 6.84 (d, J=8.76 Hz, 2H), 6.78 (d, J=8.76 Hz, 2H), 3.93-3.74 (m, 2H), 3.50-3.40 (br d, 2H), 2.90-2.70 (m, 5H), 2.40-2.25(m, 1H), 1.90-1.7 (m, 4H); LC/MS m/z 485 (MH+), C₂₉H₂₈N₂O₅=484 g/mol; purity=99%.

5.1.2.146 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-[2-(dimethylamino)ethoxy]phenyl ketone, chloride

This compound was synthesized as described in Section 5.1.2.141. In Step 6, N-(2-chloroethyl)-dimethylamine was used for alkylation.

¹H NMR (d₆-DMSO): δ10.35 (s, 1H), 10.02 (s, 1H), 7.45 (d, J=8.76 Hz, 2H), 7.37-7.29 (m, 5H), 7.26-7.20 (m, 1H), 6.86-6.83 (d, J=8.76 Hz, 2H), 6.85 (d, J=8.76 Hz, 2H), 6.79 (d, J=8.76 Hz, 2H), 4.33 (t, J=4.61 Hz, 2H), 3.47 (t, J=4.61 Hz, 2H), 2.80 (s, 6H); LC/MS m/z 445 (MH+), C₂₆H₂₄N₂O₅=444 g/mol; purity=99%.

5.1.2.147 Synthesis of 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl 3-[(1-methyl(3-piperidyl))methoxy]phenyl ketone, chloride

This compound was synthesized as described in Section 5.1.2.145. Partial demethylation afforded the mono-demethylated product by monitoring reaction progress by thin-layer chromatography.

¹H NMR (d₆-DMSO): δ10.32 (one isomer: s, 1H), 9.98 (other isomer: s, 1H), 7.57 (one isomer: d, J=8.76 Hz, 2H), 7.44 (other isomer: d, J=8.76 Hz, 2H), 7.34-7.29 (m, 2H), 7.19-7.17 (m, 1H), 7.03 (one isomer: d, J=8.76 Hz, 2H), 6.97 (other isomer: d, J=8.76 Hz, 2H), 6.84 (one isomer: d, J=8.76 Hz, 2H), 6.80-6.76 (other isomer: d, J=8.76 Hz, 2H), 3.94-3.75 (m, 5H), 3.48-3.43 (br d, 2H) 2.90-2.70 (m, 5H), 2.40-2.25 (m, 1H), 1.84 (m, 4H); LC/MS m/z 499 (MH+), C₃₀H₃₀N₂O₅=498 g/mol; purity=93%.

5.1.2.148 Synthesis of 3-[2-(dimethylamino)ethoxy]phenyl 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl ketone, chloride

This compound was synthesized as described in Section 5.1.2.146. Partial demethylation afforded the mono-demethylated product by monitoring reaction progress by thin-layer chromatography.

¹H NMR (d₆-DMSO): δ7.59-6.75 (m, 12H), 7.44 (other isomer: d, 2H, J 8.76), 4.31 (br, 2H), 3.78(one isomer: s, 3H), 3.75 (other isomer: s, 3H), 3.47 (br, 2H), 2.82 (s, 6H); LC/MS m/z 459 (MH+), C₂₇H₂₆N₂O₅=458 g/mol; purity=99%.

5.1.2.149 Synthesis of 4-[4-ethyl-3-(4-hydroxy-2-methylphenyl)isoxazol-5-yl]-3-methylphenol

This compound was synthesized by following the procedures described in Scheme 1 using 2′-methyl-4′-methoxyacetophenone and 2-methyl-4-methoxybenzoyl chloride as starting materials.

¹H NMR (d₆-Acetone): δ7.24 (d, J=8.29 Hz, 1H, ArH), 7.19 (d, J=8.29 Hz, 1H, ArH), 6.87-6.79 (m, 4H, ArH), 2.31(q, J=7.38 Hz, 2H, CH2), 2.24 (s, 3H, CH3), 2.22 (s, 3H, CH3), 0.82 (t, J=7.38 Hz, 3H, CH2CH3); LC/MS m/z 310 (MH+), C₁₉H₁₉NO₃=309 g/mol; purity=95%.

5.1.2.150 Synthesis of 4-[3-(4-hydroxyphenyl)-4-propylisoxazol-5-yl]phenol

This compound was synthesized based upon Scheme 4.

Step 1-3: Same as the corresponding steps in Section 5.1.2.20.

Step 4: Alkylation. To a solution of 4-bromoisoxazole (1 eq., obtained from step 3) in THF at −78° C. was added nBuLi (1.1 eq., 1.6 M in hexane). After the solution was stirred at −78° C. for 1.5 h, it was added dropwise into a solution of the bromopropane(1.2 eq.) in THF at −78° C. After 15 min., the solution was allowed to warm to room temperature and stirred overnight. After quenching reaction with 1 M HCl, the layers were separated and the aqueous layer extracted with EtOAc (×3). The combined organic layers were washed with saturated NaHCO₃ (×1) and brine, dried over Na₂SO₄, filtered and concentrated to afford a crude product mixture. Flash chromatography yielded the alkylated product.

Step 5. Demethylation was performed using Method 3 for Step C in Scheme 1.

¹H NMR (CDCl₃/DMSO, 6:1): δ7.29 (d, J=8.60 Hz, 2H), 7.18 (d, J=8.60 Hz, 2H), 6.70 (d, J=8.40 Hz, 2H), 6.68 (d, J=8.40 Hz, 2H), 2.34-2.39 (m, 2H), 1.21-1.24 (m, 2H), 0.58 (t, J=7.23 Hz, 3H); ESMS m/z 296 (MH+), C₁₈H₁₇NO₃=295 g/mol; HPLC purity=87.3%.

5.1.2.151 Synthesis of 4-[3-(4-hydroxyphenyl)-4-prop-2-enylisoxazol-5-yl]phenol

This compound was synthesized in the same manner as Section 5.1.2.150, except, in step 4, allylbromide was used as the alkylating agent.

¹H NMR (CDCl₃/DMSO, 6:1): δ9.10 (s, 1H), 8.93 (s, 1H), 7.23 (d, J=8.79 Hz, 2H), 7.14 (d, J=8.79 Hz, 2H), 6.59 (d, J=8.79 Hz, 2H), 6.57 (d, J=8.79 Hz, 2H), 5.69-5.78 (m, 1H), 4.87 (d, J=10.36 Hz, 1H), 4.71 (d, J=17.19 Hz, 1H), 3.01-3.02 (m, 2H); ESMS m/z 294 (MH+), C₁₈H₁₅NO₃=293 g/mol; HPLC purity=80.8%.

5.1.2.152 Synthesis of 4-[2-(diethylamino)ethylthio]phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone

This compound was synthesized by following the procedures described in Scheme 6.

Steps 1-3 were performed as described in Section 5.1.2.20.

Step 4: Performed as described in Step 4 in Section 5.1.2.20, except 4-fluorobenzoyl chloride was used for acylation.

Step 5: In a THF suspension of sodium hydride (1.1 eq.) was added 2-diethylamino-ethane thiol. The mixture was stirred at rt for 30 min., followed by addition of the compound obtained from Step 4. The reaction mixture was stirred at rt for 2 h, poured into water, extracted with ethyl acetate. The organic extracts were combined, washed with brine, dried with Na₂SO₄, and concentrated in vacuo. Purification by flash column chromatography yielded product 4-[2-(diethylamino)ethylthio]phenyl 3,5-bis(4-methoxyphenyl)isoxazol-4-yl ketone.

Step 6: Demethylation was performed using Method 2 for Step C in Scheme 1.

¹H NMR (d₆-Acetone): δ7.75 (d, J=8.76 Hz, 2H), 7.57 (d, J=8.76 Hz, 2H), 7.45 (d, J=8.76 Hz, 2H), 7.29 (d, J=7.84 Hz, 2H), 6.90 (d, J=8.76 Hz, 2H), 6.83 (d, J=8.30 Hz, 2H), 3.10 (t, J=7.83 Hz, 2H), 2,52 (t, J=7.07 Hz, 2H), 0.96 (t, J=7.14 Hz, 2H); LC/MS m/z 489 (MH+), C₂₈H₂₈N₂O₄S=488 g/mol; purity=99%.

5.1.2.153 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(dimethylamino)ethylthio]phenyl ketone

This compound was synthesized as described in Section 5.1.2.152. In Step 5, 2-dimethylamino-ethane thiol was used.

¹H NMR (d₆-Acetone): δ7.74 (d, J=8.76 Hz, 2H), 7.57 (d, J=9.22 Hz, 2H), 7.45 (d, J=8.76 Hz, 2H), 7.27 (d, J=8.76 Hz, 2H), 6.89 (d, J=9.22 Hz, 2H), 6.82 (d, J=8.76 Hz, 2H), 3.00 (t, J=7.14 Hz, 2H), 2.54 (t, J=7.14 Hz, 2H), 2.14(s, 6H); LC/MS m/z 461 (MH+), C₂₆H₂₄N₂O₄S=460 g/mol; purity=95%.

5.1.2.154 Synthesis of 4-(2-azaperhydroepinylethoxy)phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone

This compound was synthesized as described Section 5.1.2.152. In step 5, 2-azaperhydroepinylethan-1-ol was used.

¹H NMR (d₆-Acetone): δ7.82 (d, J=8.76 Hz, 2H), 7.57 (d, J=8.76 Hz, 2H), 7.47 (d, J=8.76 Hz, 2H), 6.93-6.88 (m, 4H), 6.84 (d, J=8.76 Hz, 2H), 4.10 (t, J=5.99 Hz, 2H) 2.89 (t, J=5.99 Hz, 2H), 2.72 (t, J=5.53 Hz, 2H), 1.65-1.52 (m, 6H); LC/MS m/z 499 (MH+), C₃₀H₃₀N₂O₅=498 g/mol; purity=95%.

5.1.2.155 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)-2-(trifluoromethyl)phenyl ketone

This compound was synthesized as described Section 5.1.2.152. In step 4, 2-trifluoromethyl-4-methoxybenzoyl chloride was used. In step 5, N-(2-hydroxyethyl)-piperidine was used.

¹H NMR (d₆-DMSO): δ7.56 (d, J=8.76 Hz, 1H), 7.54 (d, J=8.76 Hz, 2H), 7.27 (d, J=8.76 Hz, 2H), 7.27 (d, J=8.30 Hz, 1H), 6.86 (dd, J=8.76 Hz and 2.31 Hz, 1H), 6.81 (d, J=8.76 Hz, 2H), 6.73 (d, J=8.76 Hz, 2H), 4.12 (t, J=5.76 Hz, 2H), 3.31 (br s, 2H), 2.59 (br s, 2H), 2.38 (br m, 4H), 1.46 (br m, 4H), 1.37 (br m, 2H); LC/MS m/z 553 (MH+), C₃₀H₂₇F₃N₂O₅=552 g/mol; purity=99%.

5.1.2.156 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-{2-[(2-ethylthioethyl)amino]ethoxy}phenyl ketone

This compound was synthesized as described Section 5.1.2.152. In step 5, N-(2-hydroxyethyl)-aziridine was used.

¹H NMR (d₆-Acetone): δ7.83 (d, J=8.76 Hz, 2H), 7.57 (d, J=9.22 Hz, 2H), 7.46 (d, J=9.22 Hz, 2H), 6.94 (d, J=8.76 Hz, 2H), 6.89 (d, J=8.76 Hz, 2H), 6.83 (d, J=8.76 Hz, 2H), 4.11 (t, J=5.53 Hz, 2H), 2.98 (t, J=5.53 Hz, 2H), 2.82 (t, J=6.50 Hz, 2H), 2.63 (t, J=6.50 Hz, 2H), 2.51 (q, J=7.38 Hz, 2H), 1.17 (t, J=7.38 Hz, 2H); LC/MS m/z 505 (MH⁺), C₂₈H₂₈N₂O₅S=504 g/mol; purity=95%.

5.1.2.157 Synthesis of 3-(4-hydroxy-2-methylphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol

This compound was synthesized as described in Section 5.1.2.29 using 6-methoxy-1-tetralone and 2-methyl-4-methoxybenzoyl chloride as starting materials.

¹H NMR (d₆-acetone): δ7.75 (d, J=8.8 Hz, 1H), 7.30 (d, J=8.3 Hz, 1H), 6.86-6.80 (m, 4H), 2.91-2.72 (m, 4H), 2.34 (s, 3H); LC/MS m/z 294 (MH+), C₁₈H₁₅NO₃=293 g/mol; purity=90%.

5.1.2.158 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazole-4-carbonitrile

This compound was synthesized based upon the methodology described in Scheme 4.

Steps 1-3 were performed as described in Section 5.1.2.20.

Step 4: was also performed as described in Section 5.1.2.20 except tosyl nitrile was used as the electrophile.

Step 5: Demethylation was based upon Method 3 for Step C in Scheme 1.

¹H NMR (d₆-acetone): δ8.04 (d, J=8.8 Hz, 1H), 7.87 (d, J=8.8 Hz, 1H), 7.13 (d, J=8.8 Hz, 1H), 7.06 (d, J=8.8 Hz, 1H); LC/MS m/z 279 (MH+), C₁₆H₁₀N₂O₃=278 g/mol; purity=99%.

5.1.2.159 Synthesis of 4-[4-ethyl-5-(4-hydroxyphenyl)isoxazol-3-yl]-3-methylphenol

This compound was synthesized regiospecifically by following procedures described in Scheme 3.

Step 1: Oxime synthesis. To a suspension of 2′-methyl-4′-methoxy-acetophenone (1.0 eq.) in ethanol was added NH₂OH.HCl (1.2 eq.) and pyridine (1.2 eq.). The mixture was heated to reflux and stirred overnight. The solvent was removed under reduced pressure and the residue was dissolved in EtOAc, washed with water and brine, dried over Na₂SO₄, filtered and concentrated to afford a crude product mixture. Flash chromatography yielded the oxime as two regioisomers in 85% yield.

Step 2: isoxazole synthesis. To a solution of oxime obtained from step 1 (2 eq.) in THF at 0° C. was added n-BuLi (4.2 eq.). After 30 min, methyl 4-methoxybenzoate (1.0 eq.) was added as a solution in THF. After stirring for 30 min. at 0° C., the mixture was warmed to room temperature. HCl (10 mL, 5 N) was added and the biphasic reaction mixture was heated to reflux and stirred overnight. Upon cooling to 0° C., isoxazole precipitated and was collected via filtration. The filtrate was washed with water and the aqueous layer extracted with EtOAc (×3). The organic layers were combined, washed with saturated NaHCO₃ and brine, dried over Na₂SO₄, filtered and concentrated to afford a crude reaction mixture. Flash chromatography (THF/Hexanes) and recrystallization (THF/EtOH) yielded the isoxazole.

Step 3 Demethylation was performed as described in Method 3 of Step C of Scheme 1.

¹H NMR (d₆-acetone): δ=7.67 (d, J=8.8 Hz, 2H), 7.15 (d, J=8.4 Hz, 1H), 7.03 (d, J=8.8 Hz, 2H), 6.85 (d, J=2.5 Hz, 1H), 6.80 (dd, J=8.2, 2.5 Hz, 1H), 2.52 (q, J=7.6 Hz, 2H), 2.18 (s, 3H), 0.98 (t, J=7.6 Hz, 3H); LC/MS m/z 296 (MH=⁺), C₁₈H₁₇NO₃=295 g/mol; purity=99%.

5.1.2.160 Synthesis of 3-(4-hydroxy-2-methylphenyl)naphtho[1,2-c]isoxazol-7-ol

This compound was synthesized as described in Section 5.1.2.32 using 6-methoxy-1-tetralone and 2-methyl-4-methoxybenzoyl chloride as starting materials.

¹H NMR (d₆-acetone): δ8.31 (d, J=8.3 Hz, 1H), 7.64 (d, J=8.8 Hz, 1H), 7.52 (d, J=8.8 Hz, 1H), 7.47-7.38 (m, 3H), 6.94-6.88 (m, 2H), 2.42,2.38 (2s, 3H); LC/MS m/z 292 (MH⁺), C₁₈H₁₃NO₃=85%

5.1.2.161 Synthesis of 3-(4-hydroxyphenyl)-4,5,6-trihydrobenzo[a]isoxazolo[3,4-c][7]annulen-8-ol

This compound was synthesized in the same manner as Section 5.1.2.29, except in Step 1, 7-methoxy-1-benzosuberone was used to form the 1,3-diketone.

ESMS: m/z 294 (MH+), C₁₈H₁₅NO₃=293 g/mol; HPLC purity=80.6%.

5.1.2.162 Synthesis of 4-[3-(4-hydroxyphenyl)-4-(2-methoxyphenyl)isoxazol-5-yl]phenol

This compound was synthesis based upon Scheme 4.

Step 1-3: Same as corresponding steps in Section 5.1.2.20.

Step 4: Suzuki coupling of 4-bromoisoxazole with arylboronic acid. Reaction was carried out under an atmosphere of nitrogen and solvents were degassed by bubbling nitrogen for 2 h prior to the reaction. Pd(PPh₃)₄ (0.04 eq) in DMF was added to the 4-bromoisoxazole (obtained from step 3) and 2-methoxyphenylboronic acid (or vinyltributyltin) (1.1 eq). Sodium carbonate (0.4 mL, 2M) was then added. The reaction was sealed and allowed to stand overnight at 90° C. Ethyl acetate (20 mL) was then added and the reaction was washed with water and brine. The organic fractions were filtered and concentrated under reduced pressure. Residues were lyophilised in 90% MeCN/H₂O. Purification of the compound was achieved by teturation with 60% MeCN/H₂O and HPLC purification.

Step 5: Demethylation was following Method 3 described for Step C in Scheme 1.

¹H NMR (CDCl₃& DMSO-d₆): δ3.04 (3H, s), 6.16 (2H, d, J=8.5 Hz), 6.20 (2H, d, J=8.7 Hz),6.44 (1H, t, J=7.5 Hz), 6.47 (1H, d, J=8.4 Hz), 6.58 (1H, dd, J=7.1 Hz, 1.6 Hz), 6.67 (2H, d, J=8.5 Hz), 6.78 (2H, d, J=8.6 Hz), 6.87 (3H, t, J=8.3 Hz), 8.69 (1H, s), 8.91 (1H, s); ESMS m/z 360 (MH+), C₂₂H₁₇NO₄=359 g/mol; HPLC purity=98.2%.

5.1.2.163 Synthesis of 4-{4-[3,5-bis(trifluoromethyl)phenyl]-5-(4-hydroxyphenyl)isoxazol-3-yl}phenol

This compound was synthesized in the same manner as product in Section 5.1.2.162, except in Step 4, 3,5-di-trifluoromethylphenylboronic acid was used for coupling.

¹H NMR (CDCl₃): δ6.71 (1H, d, J=8.7 Hz), 6.73 (1H, d, J=10.8 Hz), 7.04 (1H, d, J=8.4 Hz), 7.60 (2H, s), 7.76 (1H, s), 9.25 (1H, s), 9.50 (1H, s); ESMS m/z 466 (MH+), C₂₃H₁₃F₆NO₃=465 g/mol; HPLC purity=86.4%.

5.1.2.164 Synthesis of 3-[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]phenol

This compound was synthesized in the same manner as product in Section 5.1.2.162, except in Step 4, 3-methoxyphenylboronic acid was used for coupling.

¹H NMR (CDCl₃): δ6.30 (4H, d, J=6.4 Hz), 6.33 (1H, s), 6.35 (1H, d, J=7.7 Hz), 6.44 (1H, d, J=8.1 Hz), 6.80 (1H, t, J=7.8 Hz), 6.85 (2H, d, J=7.6 Hz), 6.95 (2H, d, J=7.8 Hz), 8.64 (1H, s), 8.81 (1H, s), 8.98 (1H, s); ESMS m/z 346 (MH+), C₂₁H₁₅NO₄=345 g/mol; HPLC purity=91%.

5.1.2.165 Synthesis of 4-{3-(4-hydroxyphenyl)-4-[3-(trifluoromethyl)phenyl]isoxazol-5-yl}phenol

This compound was synthesized in the same manner as product in Section 5.1.2.162, except in Step 4, 3-trifluoromethylphenylboronic acid was used for coupling.

¹H NMR (CDCl₃): δ6.13 (2H, d, J=8.5 Hz), 6.17 (2H, d, J=8.7 Hz), 6.67 (2H, d, J=8.7 Hz), 6.87 (1H, s), 6.88 (1H, d, J=6.9 Hz), 6.97 (1H, t, J=7.9 Hz), 7.06 (1H, d, J=8.5 Hz), 8.79 (1H, s), 9.02 (1H, s); ESMS m/z 398 (MH+) C₂₂H₁₄F₃NO₃=397 g/mol; HPLC purity=99.3%.

5.1.2.166 Synthesis of 4-{3-(4-hydroxyphenyl)-4-[4-(trifluoromethyl)phenyl]isoxazol-5-yl}phenol

This compound was synthesized in the same manner as product in Section 5.1.2.162, except in step 4, 4-trifluoromethylphenylboronic acid was used for coupling.

¹H NMR (CDCl₃& DMSO-d₆): δ6.34 (2H, d, J=8.4 Hz), 6.38 (2H, d, J=8.4 Hz), 6.75 (2H, d, J=8.4 Hz), 6.88 (2H, d, J=8.2 Hz), 6.98 (2H, d, J=8.1 Hz), 7.22 (2H, d, J=8.4 Hz), 8.87 (1H, s), 9.09 (1H, s); 9.09 (1H, s); ESMS m/z 398 (MH+), C₂₂H₁₄F₃NO₃=397 g/mol; HPLC purity=98.8%.

5.1.2.167 Synthesis of 4-[3-(4-hydroxyphenyl)-4-(2-thienyl)isoxazol-5-yl]phenol

This compound was synthesized in the same manner as product in Section 5.1.2.162, except in Step 4, 2-thiophenylboronic acid was used for coupling.

¹H NMR (CDCl₃& DMSO-d₆): δ6.45 (2H, d, J=8.8 Hz), 6.48 (2H, d, J=8.8 Hz), 6.69 (1H, dt, J=3.8, 1.2 Hz), 6.79 (1H, dd, J=3.8, 1.2 Hz), 7.00 (2H, d, J=8.2 Hz), 7.11 (2H, d, J=8.2 Hz), 7.12-7.15 (1H, m), 8.90 (1H, s), 9.46 (1H, s); ESMS m/z 336 (MH+), C₁₉H₁₃NO₃S=335 g/mol; HPLC purity=87.9%.

5.1.2.168 Synthesis of 4-[3-(4-hydroxyphenyl)-4-(3-thienyl)isoxazol-5-yl]phenol

This compound was synthesized in the same manner as product in Section 5.1.2.162, except in Step 4, 3-thiophenylboronic acid was used for coupling.

¹H NMR (CDCl₃ & DMSO-d₆): δ6.32 (2H, d, J=8.8 Hz), 6.36 (2H, d, J=8.6 Hz), 6.54 (1H, d, J=4.8 Hz), 6.76 (1H, s), 6.82 (2H, d, J=8.5 Hz), 6.94 (2H, d, J=8.5 Hz), 7.01-7.03 (1H, m), 8.83 (1H, s); ESMS m/z 336 (MH+), C₁₉H₁₃NO₃S=335 g/mol; HPLC purity=94.0%.

5.1.2.169 Synthesis of 4-[3-(4-hydroxyphenyl)-4-vinylisoxazol-5-yl]phenol

This compound was synthesized in the same manner as product in Section 5.1.2.162, except in Step 4, vinylboronic acid was used for coupling.

¹H NMR (CDCl₃& DMSO-d₆): δ5.03 (1H, dd, J=11.4, 1.6 Hz), 5.06 (1H, dd, J=17.8, 1.6 Hz), 6.32 (1H, dd, J=17.8, 11.4 Hz), 6.65 (2H, d, J=9.0 Hz), 6.67 (2H, d, J=9.2 Hz), 7.19 (2H, d, J=8.8 Hz), 7.19 (2H, d, J=8.8 Hz), 8.95 (1H, s), 9.17 (1H, s); ESMS m/z 280 (MH+), C₁₇H₁₃NO₃=279 g/mol; HPLC purity=93.2%.

5.1.2.170 Synthesis of 3-(4-hydroxy-2-methylphenyl)-5-(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone

This compound is synthesized as described in Section 5.1.2.20 except, in Step 1, 4′-methoxy-2′-methylacetophenone and p-anisoylchloride are used as starting materials. A mixture of regioisomers is obtained.

ESMS m/e 499 (MH⁺), C₃₀H30N₂O₅=498 g/mol; HPLC purity=90%.

5.1.2.171 Synthesis of 3-(2-ethyl-4-hydroxyphenyl)-5-(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone

This compound is synthesized as described in Section 5.1.2.20 except, in Step 1, 4′-methoxy-2′-ethylacetophenone and p-anisoylchloride are used as starting materials. A mixture of regioisomers is obtained.

ESMS m/e 513 (MH⁺), C₃₁H₃₂N₂O₅=512 g/mol; HPLC purity=90%.

5.1.2.172 Synthesis of 3,5-bis(4-hydroxy-2-methylphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone

This compound is synthesized as described in Section 5.1.2.20 except, in Step 1, 4′-methoxy-2′-methylacetophenone and 4-methoxy-2-methylbenzoyl chloride are used as starting materials.

ESMS m/e 513 (MH⁺), C₃₁H₃₂N₂O₅=512 g/mol; HPLC purity=90%.

5.1.2.173 Synthesis of 4-(4-{(hydroxyimino)[4-(2-piperidylethoxy)phenyl]methyl}5-(4-hydroxyphenyl)isoxazol-3-yl)phenol

This compound is synthesized based upon Scheme 7.

Steps 1-7: Same as corresponding steps in Section 5.1.2.20.

Step 8: Oxime synthesis. To a suspension of the ketone obtained from Step 7 (1.0 eq.) in ethanol is added NH₂OH.HCl (1.2 eq.) and pyridine (1.2 eq.). The mixture is heated to reflux and stirred overnight. The solvent is removed under reduced pressure and the residue is dissolved in EtOAc, washed with water and brine, dried over Na₂SO₄, filtered and concentrated to afford a crude product mixture. Flash chromatography yielded the oxime as a mixture of two regioisomers.

ESMS m/e 500 (MH⁺), C₂₉H₂₉N₃O₅=499 g/mol; HPLC purity=90%.

5.1.2.174 Synthesis of 4-(4-{(1E)-2-aza-2-methoxy-1-[4-(2-piperidylethoxy)phenyl]vinyl}-5-(4-hydroxyphenyl)isoxazol-3-yl)phenol

This compound is synthesized in the same manner as the above compound except in Step 8, methoxyamine was used to form the oxime.

ESMS m/e 514 (MH⁺), C₃₀H₃₁N₃O₅=513 g/mol; HPLC purity=90%.

5.1.2.175 Synthesis of 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(tert-butoxy)ethoxy]phenyl ketone

This compound is synthesized in the same manner as Section 5.1.2.152. In step 5, 2-(tert-butoxy)ethan-1-ol is used as the nucleophile.

ESMS m/e 474 (MH⁺), C₂₈H₂₇NO₆=473 g/mol; HPLC purity=90%.

5.1.2.176 Synthesis of 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone

This compound is synthesized based upon Scheme 3 and Scheme 6.

Step 1 and 2: Same as corresponding steps in Section 5.1.2.152 except 4′-benzyloxyacetophenone is used to form oxime in Step 1.

Step 3-5: Same as corresponding steps in Section 5.1.2.152 except 2-piperidylethan-1-ol is used in Step 5 as the nucleophile.

Step 6: Selective removal of benzyl protecting group. To the above obtained compound in MeOH solution was added 10% Pd/C (catalytic amount). The mixture is stirred under hydrogen atmosphere (balloon) at rt overnight, and filtered through celite pad. Ethyl acetate is used to wash the residue. The filtrate is concentrated and subjected to purification to yield the title compound.

ESMS m/e 499 (MH⁺), C₃₀H₃₀N₂O₅=498 g/mol; HPLC purity=90%.

5.1.2.177 Synthesis of 3,5-bis(4-hydroxyphenyl)-4-{[4-(2-piperidylethoxy)phenyl]sulfonyl}isoxazole

This compound is synthesized based on Scheme 6.

Steps 1-3: Same as corresponding steps in Scheme 5.1.2.20.

Step 4: Same as Step 4 in Scheme 5.1.2.20 except, 4-fluorophenylsulfonyl chloride is used as the electrophile to quench the isoxazole anion.

Step 5: Same as Step 5 in the above example.

Step 6: Demethylation was performed using Method 3 described for Step C in Scheme 1.

ESMS m/e 521 (MH⁺), C₂₈H₂₈N₂O₆S=520 g/mol; HPLC purity=90%.

5.1.2.178 Synthesis of 3(4-hydroxyphenyl)isoxazolo[4,3-c]quinolin-7-ol

Step 1: Formation of 1,3-diketone. Same as Step 1 in Section 5.1.2.7 except, 2-fluoro-4-methoxyacetophenone and p-anisoyl chloride were used as starting materials.

Step 2: To a THF solution of the above 1,3-diketone was added dimethylformamidedimethylacetal (4 eq.) The mixture was heated to reflux for 16 h and concentrated in vacuo to give a dark residue. Purification with column chromatography afforded 2-[(dimethylamino)methylene]-3-(2-fluoro-4-methoxyphenyl)-1-(4-methoxyphenyl)propane-1,3-dione.

Step 3: The above intermediate is mixed with ammonia under pressure (a bomb equipment) and heated to 60° C. overnight. The reaction is cooled to −78° C. and allowed ammonia to evaporate. To the residue is added water and EtOAc. Routine extraction followed by concentration then gives the crude product, which is purified to give quinolone product.

Step 4: Formation of isoxazole heterocycle. Same as step 4 in Section 5.1.2.7 except, using compound obtained above as starting material. This step gives 7-methoxy-3-(4-methoxyphenyl)isoxazolo[4,3-c]quinoline as product.

Step 5: Demethylation is performed using Method 3 described for Step C in Scheme 1.

ESMS m/e 279 (MH⁺), C₁₆H₁₀N₂O₃=278 g/mol; HPLC purity=90%.

5.1.2.179 Synthesis of (2E)-3-(4-{[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]carbonyl}phenyl)prop-2-enoic acid

Step 1-3: Same as corresponding steps in Section 5.1.2.20.

Step 4: Suzuki coupling was used to introduce the phenyl ring. The isoxazole obtained from step 3 is dissolved in toluene and degassed with argon for 10 min. To this solution is added Pd(PPh₃)₄ (4.0 mol %). After an additional 10 min, Na₂CO₃ (5 eq.) is added followed by a solution of 4-formylphenyl boronic acid (1.1 rq.) in ethanol. The reaction is heated to reflux and stirred for 16 h. The reaction mixture is then poured into a separatory funnel and the aqueous layer extracted twice with ethyl acetate. The organic layers are combined, washed with a brine solution and dried over Na₂SO₄. Purification by flash chromatography (40% ethyl acetate/hexanes) then give the product.

Step 5: Honor-Emmons reaction to form α,β-unsaturated ester. The above product is subjected to Honor-Emmons reaction condition using trimethyl phosphonoacetate to afford methyl (2E)-3-{4-[3,5-bis(4-methoxyphenyl)isoxazol-4-yl]phenyl}prop-2-enoate.

Step 6: Saponification (NaOH in water/THF) of the above compound then gives (2E)-3-{4-[3,5-bis(4-methoxyphenyl)isoxazol-4-yl]phenyl}prop-2-enoic acid.

Step 7: Demethylation is performed using Method 3 described for Step C in Scheme 1.

ESMS m/e 400 (MH⁺), C₂₄H₁₇NO₅=399 g/mol; HPLC purity=90%.

5.1.2.180 Synthesis of 7-hydroxy-3-(4-hydroxyphenyl)(4,5-dihydroisoxazolo[4,3-c]quinolin-5-yl) 4-(2-piperidylethoxy)phenyl ketone

Steps 1-3: Same as Section 5.1.2.178.

Step 4: Reduction. To a methanol solution of the compound obtained from step 3 is added 10% Pd/C. The mixture is stirred under hydrogen atmosphere (balloon) at rt overnight, and filtered through celite pad. Ethyl acetate is used to wash the residue. The filtrate is concentrated and subjected to purification to yield product as 7-methoxy-3-[(4-methoxyphenyl)carbonyl]-1,2,3-trihydroquinolin-4-one.

Step 5: Formation of isoxazole heterocycle. Same as step 4 in Section 5.1.2.7 except, using compound obtained above as starting material. This step gives 7-methoxy-3-(4-methoxyphenyl)-4,5-dihydroisoxazolo[4,3-c]quinoline as the product.

Step 6: Acylation. To a suspension of sodium hydride (1.1 eq) in THF is added the above compound (1.0 eq.) at 0° C. The mixture is stirred at rt for 1 h or until the bubbling stops. To this is added 4-(2-piperidylethoxy)benzoyl chloride in THF solution. This mixture is stirred at rt overnight, poured into water followed by routine extraction procedure to give a crude product which is purified to yield 7-methoxy-3-(4-methoxyphenyl)(4,5-dihydroisoxazolo[4,3-c]quinolin-5-yl) 4-(2-piperidylethoxy)phenyl ketone.

Step 7: Demethylation is performed using Method 3 described for Step C in Scheme 1.

ESMS m/e 512 (MH⁺), C₃₀H₂₉N₃O₅=511 g/mol; HPLC purity=90%.

5.1.2.181 Synthesis of 2-[4-ethyl-5-(4-hydroxyphenyl)isoxazol-3-yl]-5-hydroxybenzenecarbonitrile

Same procedure as Section 5.1.2.92 except, in step 3, tosyl nitrile was used as the electrophile and in step 4, demethylation was using Method 3 for Step C in Scheme 1.

ESMS m/z 307 (MH+), C₁₈H₁₄N₂O₃=306 g/mol, HPLC purity=99%

5.1.2.182 Synthesis of 2-[4-ethyl-5-(4-methoxyphenyl)isoxazol-3-yl]-5-hydroxybenzenecarbonitrile

Partial demethylation yielded of the compound synthesized as described in Section 5.1.2.181 provided the title compound.

ESMS m/z 321 (MH+), C₁₉H₁₆N₂O₃=320 g/mol, HPLC purity=99%

5.2 Biological Activity of Compounds of the Invention

5.2.1 In vivo Assays

5.2.1.1 Allen-Doisy Test for Estrogenicity

This test is used to evaluate a test compound for estrogenic activity by observation of cornification of the vaginal epithelium of in ovariectornized rats after administration of a test compound (Allen and Doisy 1923; Mühlbock 1940; Terenius 1971).

Mature female Hsd/Cpb rats, having initial weights between about 150-200 g, were obtained from a commercial supplier (Harlan-CPB, Horst, The Netherlands). The rats were housed in housed in aluminium cages in a light- and temperature-controlled room (14 hours light/10 hours dark at 19° C.-23° C.). Four rats were housed per cage. The rats were provided free access to standard pelleted food and to tap water. After a period of acclimatization (a few days) the rats were ovariectornized bilaterally under ether anaesthesia. Vaginal smears were taken over a period of 4-5 days. Rats showing positive smears were discarded.

The rats of each treatment group were housed in two juxtaposed cages. Each experiment consisted of 2+n groups of eight rats per group. Two reference groups received the reference compound (estradiol, 1, 3, 5 (10)-estratriene-3, 17-β-diol for subcutaneous (“sc”) administration; ethinylestradiol for oral administration); n groups received the test compound. For subcutaneous administration, between 0.1 μg and 0.2 μg total dose/rat (approx. 0.4-0.8 μg/kg total dose) was used. For oral administration, 0.008-0.016 mg total dose/rat (approx. 0.032-0.064 mg/kg total dose) was used. Vehicles used for sc administration were (in preferential order): arachis oil, arachis oil with 100 ml/l benzyl alcohol; gelatin (5.0 g/l) and mannitol (50 g/l) in water; methylcellulose (2.0 g/l) and NaCl, (9.0 g/l) in water; or any other suitable vehicle. For oral administration, the vehicles used were (in preferential order): gelatin (5.0 g/l) and mannitol (50 g/l) in water; methylcellulose (2.0 g/l) and NaCl, (9.0 g/l) in water; mulgofen (50 g/l) (sold under the tradename ELF 719, GAF) and NaCl (9.0 g/l) in water; or any other suitable vehicle.

Three weeks after ovariectomy, the rats were primed with a single sc dose of 1 μg estradiol (in 0.1 ml arachis oil) to ensure maintenance of sensitivity and greater uniformity of response. In the fourth week, 7 days after priming, (preferably on a Monday), the reference or test compound was administered in 3 equal doses, one in the afternoon of the first day of treatment, and two (one in the morning and one in the afternoon) of the second day of treatment. Compound doses were chosen based on extrapolations of in vitro data obtained in the CHO-transactivation (Section) and/or binding assays for estrogen receptor using known estrogen agonists and antagonists. For sc administration, the reference compound (estradiol) was administered in total doses of 0.1-0.2 μg/rat. Test compounds were usually administered in total doses of 0.01-1.0 mg/rat. Each total sc dose was divided equally over three administrations, each in a dose volume of 0.25 ml. For oral administration, the reference compound (ethinylestradiol) was administered in total doses of 0.008-0.016 mg/rat. Test compounds are usually administered in total doses of 0.01-1.0 mg/rat. Each total oral dose was divided equally over 3 administrations, each in a dose volume of 0.25 ml. For expression of doses per kg, an average body weight of 250 g was assumed. Vaginal smears were taken in the afternoon of the third day, in the morning and afternoon of the fourth day, and in the morning of the fifth day of the treatment week. Additional vaginal smears were taken on succeeding days (in the morning) until the estrogenic response was complete. The vaginal smears were made on microscope slides. The slides were dried and fixed with 96% ethanol, and stained for about twenty minutes with Giemsa solution (Merck, Darmstadt, Germany), that had been diluted 1:10 with tap water, washed thoroughly under tap water, then dried. The percentage of cornified and nucleated epithelial cells was estimated for each smear was evaluated under microscope observation (60×). The rats were allowed to rest for one week (week five of the experiment). The experiment was then repeated, with priming on the sixth week and administration and observation during the seventh week, as described. The rats were then euthanized under deep anesthesia or with CO₂/O₂ gas.

The developmental phase of the vaginal epithelium for each rat was evaluated using a scale from “a”-“g” determined as follows (Table 1). The vaginal sequence of normal non-ovariectornized rats with a 4-day estrous cycle is: diestrus→diestrus→proestrus→estrus. The usual phases observed in the mornings of the 4-day estrous cycle using the scale in Table 1 are therefore a, a, e, and g, respectively. The phases b, c, d and f are intermediates.

TABLE 1 Percentage Percentage Percentage Of of Nucleated of Cornified Developmental Leucocytes Epithelial Cells Epithelial Cells Phase >67% — — a. diestrus 5-50% >50% — b. late diestrus <5% >50% — e. proestrus <5% — >50% f. esters <5% <5% >90% g. estrus 5-33% — >50% d. metestrus 33-67% — <50% c. late metestrus

The number of rats with a positive response is a measure for the estrogenic activity of the test compound. The interpretation of the results was made as shown in Table 2.

TABLE 2 Percentage of Rats Showing a Positive Response Conclusion 0% inactive 1%-50% weakly active >50% active

5.2.1.2 Ant-Allen-Doisy Test for Anti-Estrogenicity

This test is used to evaluate a test compound for anti-estrogenic activity when administered in the presence of estrogen (Allen and Doisy 1923; Jongh and Laqueur 1938; Mühlbock 1940; Emmens, Cox et al. 1959). More specifically, the ability of the test compound to counteract the estrogenic cornification of vaginal epithelium is determined.

Mature female Cpb rats, having initial weights between about 150-200 g, were obtained from a commercial supplier (CPB-TNO, Zeist, The Netherlands). The rats were housed in housed in aluminium cages in a light- and temperature-controlled room (14 hours light/10 hours dark at 21° C.-23° C.). Four rats were housed per cage. The rats were provided free access to standard pelleted food and to tap water. After a period of acclimatization (a few days) the rats were ovariectornized bilaterally under ether anaesthesia. Vaginal smears were taken over a period of 4-5 days. Rats showing positive smears were discarded.

The rats of each treatment group were housed in two juxtaposed cages. Each experiment consisted of 1+n groups of eight rats per group. One reference group received the reference compound (nafoxidine HCl); n groups received the test compound. For oral administration, 0.25 mg/rat/day (approx. 1.44 mg/kg/day) was used. Vehicles used for subcutaneous (“sc”) administration were (in preferential order): arachis oil, arachis oil with 10% benzyl alcohol; gelatin (0.5%) and mannitol (5%) in water; and methylcellulose (0.2%) and NaCl (9.0% ) in water. For oral administration, the vehicles used were (in preferential order): gelatin (0.5%) and mannitol (5%) in water; methylcellulose (0.2%) and NaCl (9.0% ) in water; and mulgofen (5%) (sold under the tradename ELF 719, GAF) and NaCl (0.9%) in water.

Two weeks after ovariectomy, the rats were primed with a single sc dose of 0.2 μg estradiol (in 0.1 ml arachis oil) administered daily for ten days to ensure maintenance of sensitivity and greater uniformity of response. Administration of estradiol was followed immediately by administration of test compound or vehicle. Test compounds were administered at 1.0 mg/rat. For sc administration, the dose volume was 0.1 ml; for oral administration, the dose volume was 0.25 ml. Vaginal smears were taken daily throughout the administration period. The vaginal smears were made on microscope slides. The slides were dried and fixed with 96% ethanol, and stained for about twenty minutes with Giemsa solution (Merck, Darmstadt, Germany), that had been diluted 1:10 with tap water, washed thoroughly under tap water, then dried. The percentage of cornified and nucleated epithelial cells was estimated for each smear was evaluated under microscope observation (60×). Following the experiment, rats were euthanized under deep anesthesia or with CO₂/O₂ gas.

The developmental phase of the vaginal epithelium for each rat was evaluated using a scale from “a”-“g” determined as follows (Table 3). The vaginal sequence of normal non-ovariectornized rats with a 4-day estrous cycle is: diestrus→diestrus→proestrus→estrus. The usual phases observed in the mornings of the 4-day estrous cycle using the scale in Table 3 are therefore a, a, e, and g, respectively. The phases b, c, d and f are intermediates.

TABLE 3 Percentage Percentage Percentage Of of Nucleated of Cornified Developmental Leucocytes Epithelial Cells Epithelial Cells Phase >67% — — a. diestrus 5-50% >50% — b. late diestrus <5% >50% — e. proestrus <5% — >50% f. estrus <5% <5% >90% g. estrus 5-33% — >50% d. metestrus 33-67% — <50% c. late metestrus

Smears showing any of phases e, f, or g were considered to be estrogenic (i.e., the vaginal epithelium showed cornification). The final result was expressed as a ratio of the number of smears showing estrogenic response to the total number of smears collected from the third day through the final day of the study. The number of rats with a positive response is a measure for the anti-estrogenic activity of the test compound. The interpretation of the results was made as shown in Table 4.

TABLE 4 Percentage of Rats Showing a Positive Response Conclusion >70% inactive 35%-70% weakly active <35% active

5.2.1.3 Immature Rat Uterotrophic Bioassay for Estrogenicity and Ant-Estrogenicity

Antiestrogenic activity is determined by the ability of a test compound (3,5-bis(4-hydroxyphenyl)isoxazol4-yl 4-(2-piperidylethoxy)phenyl ketone) to suppress the increase in uterine wet weight resulting from the administration of 0.2 μg 17-β-estradiol (“E₂”) per day. Any statistically significant decreases in uterine weight in a particular dose group as compared with the E₂ control group are indicative of anti-estrogenicity.

One hundred sixty (160) female pups (10 per foster dam) were received at 12 days of age. One hundred forty (140) female pups (19 days old) in the 35-50 g body weight range were selected for the study. On day 19 of age, when the pups weighed approximately 35-50 g, they were body weight-order randomized into treatment groups. Observations for mortality, morbidity, availability of food and water, general appearance and signs of toxicity were made twice daily. Pups not used in the study were euthanized along with the foster dams. Initial body weights were taken just prior to the start of treatment at day 19 of age. The final body weights were taken at necropsy on day 22 of age.

Treatment commenced on day 19 of age and continued until day 20 and 21 of age. Each animal was given three subcutaneous (“sc”) injections daily for 3 consecutive days. Three rats in each of the control and mid- to high-level dose test groups were anesthetized with a ketamine/xylazine mixture. Their blood was collected by exsanguination using a 22 gauge needle and 5 ml syringe flushed with 10 USP units sodium heparin/ml through the descending vena cava; and then transferred into a 5 ml green top plasma tube (sodium heparin (freeze-dried), 72 USP units). Plasma samples were collected by centrifugation, frozen at −70° C., and analyzed using mass spectrographic to determine the presence and amount of test compound in the serum. Blood chemistry was also analyzed to determine other blood parameters. The uteri from the rats were excised and weighed. The remaining rats were sacrificed by asphyxiation under CO₂. The uteri from these rats were excised, nicked, blotted to remove fluid, and weighed to the nearest 0.1 mg.

In order to determine whether the test compound significantly affected final body weight, a parametric one-way analysis of variance (ANOVA) was performed (SIGMASTAT version 2.0, available commercially from Jandel Scientific, San Rafael, Calif.). Estrogen agonist and antagonist activity was assessed by comparing uterine wet weights across treatment groups using a parametric ANOVA on loglo transformed data. The data were transformed to meet assumptions of normality and homogeneity of variance of the parametric ANOVA. The F value was determined to be significant (p<0.05) and a Student-Newman-Kuels multiple range test was performed to determine the presence of significant differences among the treatment groups. Since the final body weights were not significantly different across treatment groups (p=0.999), uterine weight:body weight ratios were not compared.

The test compound was determined to act as a mixed estrogen agonist/antagonist. The uterotrophic response was submaximal compared to that seen with the reference estrogen, 17β-estradiol. Submaximal uterotrophic response, even at elevated dose levels, is characteristic of partial estrogen agonists. When the test compound was tested in combination with 17β-estradiol, partial inhibition of the uterotrophic response was observed at all three dose levels; hence, the test compound possessed estrogen antagonist activity. However, the test compound did not completely inhibit the 17β-estradiol-stimulated uterotrophic response; implying that it is a mixed estrogen agonist/antagonist in this bioassay.

5.2.1.4 Estrogen Receptor Antagonist Efficacy In MCF-7 Xenograft Model

MCF-7 human mammary tumors from existing in vivo passages are implanted subcutaneously into 95 female Ncr-nu mice. A 17-β-estradiol pellet (Innovative Research of America) is implanted on the side opposite the tumor. Both implants are performed on the same day.

Treatment is started when the tumor sizes are between 75 mg and 200 mg. Tumor weight is calculated according to the formula for the volume of an ellipsoid, $\frac{l \times w^{2}}{2}$

where l and w are the larger- and smaller dimensions of the tumor and unit tumor density is assumed. The test compounds are administered BID: q7h×2, with one drug preparation per week. The test compounds are stored at +4° C. between injections. The dose of test compound is determined according to the individual animal's body weight on each day treatment. Gross body weights are determined twice weekly, starting the first day of treatment. Mortality checks are performed daily. Mice having tumors larger than 4,000 mg, mice having ulcerated tumors, as and moribund mice are sacrificed prior to the day of study termination. The study duration is limited to 60 days from the day of tumor implantation but termination could occur earlier as determined to be necessary. Terminal bleeding of all surviving mice is performed on the last day of the experiment. Statistical analysis is performed on the data gathered, including mortality, gross individual and group average body weights at each weighing, individual tumor weights and median group tumor weight at each measurement, the incidence of partial and complete regressions and tumor-free survivors, and the calculated delay in the growth of the median tumor for each group.

5.2.1.5 OVX Rat Model

This model evaluates the ability of a compound to reverse the decrease in bone density and increase in cholesterol levels resulting from ovariectomy (Black, Author et al. 1994; Willson, Author et al. 1997). Three-month old female rats are ovariectornized (“ovx”), and test compounds are administered daily by subcutaneous route beginning one day post-surgery. Sham operated animals and ovx animals with vehicle control administered are used as control groups. After 28 days of treatment, the rats are weighed, the overall body weight gains obtained and the animals euthanized. Blood bone markers (e.g., osteocalcin and bone-specific alkaline phosphatase), total cholesterol, and urine markers (e.g., deoxypyridinoline and creatinine) are measured. Uterine wet weights are also obtained. Both tibiae and femurs are removed from the test animals for peripheral quantitative computed tomography scanning or other measurement of bone mineral density. Data from the ovx and test vehicle animals are compared to the sham and ovx control animals to determine tissue specific estrogenic/antiestrogenic effects of the test compounds.

5.2.2 In vitro Assays

5.2.2.1 ERα Binding Assays

ERα receptor (˜0.2 mg/ml, Affinity Bioreagents) was diluted to about 2×10⁻³ mg/ml in phosphate-buffered saline (“PBS”) at a pH of 7.4. Fifty microliters 1 of the ERα-PBS solution was then added to each the wells of a flashplate (Wallac SCINTISCTRIPS). The plates were sealed and stored in the dark at 4° C. for 16-18 hours. The buffered receptor solution is removed just prior to use, and the plates were washed 3 times with 200 microliters per well of PBS. The washing was typically performed using a slow dispense of reagent into the wells to avoid stripping the receptor from the well surface.

For library screening, 150 microliters of 1 nM ³H-estradiol (New England Nuclear, Boston, Mass.) in 20 mM Tris-HCl, 1 mM EDTA, 10% glycerol, 6 mM monothioglycerol, 5 mM KCl, pH 7.8 was mixed with 50 microliters of the test compound (in same buffer) in a 96 well mictrotiter plate (Costar 3794), resulting in a final estradiol concentration of 0.6 nM. In addition, several dilutions of estradiol, centered on the IC₅₀ of 1-2 nM were also added to individual wells to generate a standard curve. The plates were gently shaken to mix the reagents. A total of 150 microliters from each of the wells is added to the corresponding wells of the pre-coated ERα plates. The plates were sealed (Packard #6005185) and the components in the wells were incubated either at room temperature for 4 hours or at 4° C. overnight. The receptor bound ligand was read directly after incubation using a scintillation counter (TRILUX, Wallac). The amount of receptor bound ligand was determined directly, i.e., without separation of bound from free ligand. If estimates of both bound and free ligand were required, the supernatant was removed from the wells, liquid scintillant added, and the wells counted separately in a liquid scintillation counter.

5.2.2.2 ERβ Binding Assays

ERβ receptor (˜0.2 mg/ml, Affinity Bioreagents) was diluted to about 2×10⁻³ mg/ml in phosphate-buffered saline (“PBS”) at a pH of 7.4. Fifty microliters of the ERβ-PBS solution was then added to each the wells of a flashplate (Wallac SCINTISCTRIPS). The plates were sealed and stored in the dark at 4° C. for 16-18 hours. The buffered receptor solution is removed just prior to use, and the plates were washed 3 times with 200 microliters per well of PBS. The washing was typically performed using a slow dispense of reagent into the wells to avoid stripping the receptor from the well surface.

For library screening, 150 microliters of 1 nM ³H-estradiol (New England Nuclear, Boston, Mass.) in 20 mM Tris-HCl, 1 mM EDTA, 10% glycerol, 6 mM monothioglycerol, 5 mM KCl, pH 7.8 was mixed with 50 microliters of the test compound (in same buffer) in a 96 well mictrotiter plate (Costar 3794), resulting in a final estradiol concentration of 0.6 nM. In addition, several dilutions of estradiol, centered on the IC₅₀ of 1-2 nM were also added to individual wells to generate a standard curve. The plates were gently shaken to mix the reagents. A total of 150 microliters from each of the wells is added to the corresponding wells of the pre-coated ERβ plates. The plates were sealed (Packard #6005185) and the components in the wells were incubated at room temperature either for 4 hours or at 4° C. overnight. The receptor bound ligand was read directly after incubation using a scintillation counter (TRILUX, Wallac). The amount of receptor bound ligand was determined directly, i e., without separation of bound from free ligand. If estimates of both bound and free ligand were required, the supernatant was removed from the wells, liquid scintillant added, and the wells counted separately in a liquid scintillation counter.

5.2.2.3 ERα/ERβ Transactivation Assays

5.2.2.3.1 Construction of Transfected CHO Cells

The above-mentioned transfected CHO cells were derived from CHO KI cells obtained from the American Type Culture Collection (“ATCC”, Rockville, Md.). The transfected cells were modified to contain the following four plasmid vectors: (1) pKCRE with DNA for the human estrogen receptor, (2) pAG-60-neo with DNA for the protein leading to neomycin resistance, (3) pRO-LUC with DNA for the rat oxytocin promoter and for firefly luciferase protein, and (4) pDR2 with DNA for the protein leading to hygromycine resistance. All transformations with these genetically modified CHO cells were performed under rec-VMT containment according to the guidelines of the COGEM (Commissie Genetische Modificatie). Screening was performed either in the absence of estradiol (estrogenicity) or in the presence of estradiol (anti-estrogenicity).

Reagents

The following reagents were prepared using ultra pure water (milli-Q quality):

1. Culture Medium

Dulbecco's MEM/HAM F12 powder (12.5 g/l; Gibco, Paisley, UK) was dissolved in water. Sodium bicarbonate (2.5 grams/liter (“g/l”)), L-glutamine (0.36 g/l) and sodium pyruvate (5.5×10⁻² g/l) were added. This medium was supplemented with an aqueous mixture (0.50 ml/l medium) of ethanolamine (2.44 ml/l), sodium selenite (0.9 mg/l), and 2-mercaptoethanol (4.2 ml/l). The pH of the medium was adjusted to 7.0±0.1 with NaOH or HCl (1 mol/l), and the medium was sterilized by membrane filtration using a filter having 0.2 μm pores. The resulting serum-free culture medium was stored at 4° C.

2. Antibiotics Solution

Streptomycin sulfate (25 g; Mycofarm, Delft, The Netherlands) and sodium penicillin G (25 g; Mycofarm) were dissolved in 1 l water and sterilized by membrane filtration using a filter having 0.2 μm pores.

3. Defined Bovine Calf Serum Supplemented (“DBCSS”)

DBCSS (Hyclone, Utah), sterilized by the manufacturer, was inactivated by heating for 30 min at 56° C. with mixing every 5 min. Aliquots of 50 ml and 100 ml were stored at −20° C.

4. Charcoal-Treated DBCSS (“cDBCSS”)

Charcoal (0.5 g; Norit A) was washed with 20 ml water (3 times) and then suspended in 200 ml Tris buffer. For coating 0.05 g dextran (T70; Pharmacia, Sweden) is dissolved in a suspension that was stirred continuously for 3 hours at room-temperature. The resulting dextran-coated charcoal suspension was centrifuged for 10 min at 8,000 N/kg. The supernatant was removed and 100 ml DBCSS was added to the residue. The suspension was stirred for 30 min at 45° C. under aseptic conditions. Following stirring, the charcoal was removed by centrifugation for 10 min at 8000 N/kg. The supernatant was sterilized by membrane filtration using a first filter having a pore size of 0.8 μm followed by filtration with a second filter having a pore size of 0.2 μm. The sterilized, heat-inactivated cDBCSS was stored at −20° C.

5. Tris Buffer

Tromethamine (“Tris”, 1.21 g; 10 mmol) was dissolved in approximately 950 ml water. The solution pH was adjusted to 7.4 using HCl (0.2 mol/l) and the volume raised to 1 l with additional water. This buffer was prepared fresh prior to use.

6. Luclite Substrate Solution

Luclite luminescense kit, developed for firefly luciferase activity measurements in microtiter plates was obtained from a commercial source (Packard, Meriden, Conn.). Ten milliliters of the above-described buffer solution was added to each flask of substrate.

Preparation of Transfected Cells

Under aseptic conditions, the above-described culture medium was supplemented with antibiotics solution (2.5 ml/l) and heat-inactivated cDBCSS (50 ml/l) to give complete medium. One vial of the above-described recombinant CHO cells was taken from the seed stock in liquid nitrogen and allowed to thaw in water at approximately 37° C. A Roux flask (80 cc) was inoculated with about 5×10⁵ viable cells/ml in complete medium. The flask was flushed with 5% CO₂ in air until a pH of 7.2-7.4 resulted. The cells were subsequently incubated at 37° C. During this period, the complete medium was refreshed twice.

Following incubation the cell culture was trypsinized and inoculated at 1:10 dilution in a new flask (180 cc cell culturing) and at 5×10³ cells with 100 μl complete medium per well in a 96-well white culture plate for transactivation assays. The 96 well plates were incubated over two days. The cells were grown as a monolayer at the bottoms of the wells and reached confluence after two days. After a cell culture period of 20 passages, new cells were taken from the seed stock in liquid nitrogen.

5.2.2.3.2 Assay of Compounds

Assay for Estrogenicity

Experiments were performed in groups of three blocks, each block in a separate microtiter plate. Each block included the following four groups

Group Contents 1 One transactivation group of four wells, each containing ethanol and transfected cells. This group was used to estimate total transactivation. 2 One total transactivation group of four wells containing beta-estradiol (1 × 10⁻⁷M) and transfected cells. This group was used to estimate total transactivation of cells. 3 Three standard groups of five wells each, containing five different concentrations of non-transfected and transfected cells. 4 Test or reference compound groups (η groups, η ≦21) of three wells each, containing three different concentrations of test or reference compound and transfected cells.

Aliquots of ten μl of control, standard, test, and reference compounds were added by pipette into wells of the relevant groups as defined above. Each of the wells included 190 μl of complete medium.

Group Contents 1 Ethanol 2 Standard solution in ethanol (10⁻⁹M, to be raised to 10⁻⁶ M final concentration). 3 Standard solutions in ethanol (0.47 × 10⁻¹¹M, 0.95 × 10⁻¹¹ M, 1.95 × 10⁻¹¹M, 3.9 × 10⁻¹¹M, and 7.8 × 10⁻¹¹M, to be raised to 0.47 × 10⁻⁸M, 0.95 × 10⁻⁸M, 1.95 × 10⁻⁸M, 3.9 × 10⁻⁸M, and 7.8 × 10⁻⁸M respectively). 4 Test or reference compound in six different concentrations 1 × 10⁻⁵M, 3.16 × 10⁻⁶M, 1 × 10⁻⁶M, 3.16 × 10⁻⁷M, 1 × 10⁻⁷M, 3.16 × 10⁻⁸M, respectively.

Assay for Anti-Estrogenicity

Experiments were performed in groups of three blocks, each block in a separate microtiter plate. Each block included the following four groups, each group containing estradiol, 1, 3, 5 (10)estratriene-3, 17-β-diol (10⁻¹⁰ M) in the final reaction mixture.

Group Contents 1 One transactivation group of four wells, each containing ethanol and transfected cells. This group was used to estimate total transactivation. 2 One group of completely inhibited transactivation group of four wells containing ICI 164,384 (10⁻⁶M) and transfected cells. This group was used to estimate complete inhibition of transactivation. 3 Three standard groups of five wells each, containing five different concentrations of non-transfected and transfected cells. 4 Test or reference compound groups (η groups, η ≦21) of three wells each, containing three different concentrations of test or reference compound and transfected cells.

Aliquots of ten μl of control, standard, test, and reference compounds were added by pipette into wells of the relevant groups as defined above. Each of the wells included 190 μl of complete medium.

Group Contents 1 Ethanol 2 Standard solution in ethanol (10⁻⁹M, to be raised to 10⁻⁶ M final concentration). 3 Standard solutions in ethanol (0.47 × 10⁻¹¹M, 0.95 × 10⁻¹¹ M, 1.95 × 10⁻¹¹M, 3.9 × 10⁻¹¹M, and 7.8 × 10⁻¹¹M, to be raised to 0.47 × 10⁻⁸M, 0.95 × 10⁻⁸M, 1.95 × 10⁻⁸M, 3.9 × 10⁻⁸M, and 7.8 × 10⁻⁸M respectively). 4 Test or reference compound in six different concentrations 1 × 10⁻⁵M, 3.16 × 10⁻⁶M, 1 × 10⁻⁶M, 3.16 × 10⁻⁷M, 1 × 10⁻⁷M, 3.16 × 10⁻⁸M, respectively.

The microtiter plates were shaken for at least 15 minutes to ensure dissolution of all compounds. Simultaneously, 100 μl estradiol, 1, 3, 5 (10)-estratriene-3, 17-β-diol (10⁻⁷ M) was added to 40 ml of complete medium, shaken, and equilibrated to 37° C. About 100 μl of this solution was added to microtiter white culture plates seeded the previous day with 10⁴ transfected cells in 100 μl of complete medium. The microtiter white culture plates were gently shaken for at least 15 minutes and incubated for 16 h at 37° C. in the dark under a humidified atmosphere flushed with 5% CO₂ in air.

Finally, 200 μl of complete medium was removed from the microtiter culture plates, while 50 μl of LUCLITE substrate solution was added to the remaining 50 μl of medium and cells. After ten minutes cell, cell lysis was substantially complete. After sealing the top of the plate, luciferase activity was measured with a luminescence counter. Each sample was counted once for 2.5 s using a scintillation (luminescence) counter. All luminescence measurements were recorded on a teleprinter.

5.2.2.3.3 Evaluation of Responses

The counting figures are corrected to a standardized plate and converted into numbers of light flashes per second (“cps”). For each block (microtiter plate), the mean cps values for the total and non-specific transactivation groups were calculated. For each concentration of standard (separate for each well), test and reference compound, the percentage of transactivation activity relative to the maximum specific estradiol, 1, 3, 5 (10)-estratriene-3, 17-β-diol transactivation activity was calculated using the formula: $\frac{\begin{matrix} {{{cps}\quad \left( {{{standard}/{test}}{\quad \quad}{compound}}\quad \right)} -} \\ {{mean}\quad {cps}\quad \left( {{non} - {{specific}{\quad \quad}{transactivation}}}\quad \right)} \end{matrix}}{\begin{matrix} {{{cps}\quad \left( {{total}{\quad \quad}{transactivation}}\quad \right)} -} \\ {{mean}\quad {cps}\quad \left( {{non} - {{specific}{\quad \quad}{transactivation}}}\quad \right)} \end{matrix}} \times 100.$

The percentage in the three blocks was evaluated statistically using the analysis of a 3-point parallel line assay in blocks. In order to meet better the requirements for this analysis, the percentages were replaced by their logit values. The log concentration-response curves for the standard, test, and reference compounds were tested for linearity; and the latter curves also for parallelism with the curve for the standard compound. If no significant curvature and no significant deviation from parallelism at the 0.01 levels were found; then the relative transactivation activity of the test compound with respect to estradiol, 1, 3, 5 (10)-estratriene-3, 17-β-diol (potency ratio), together with the 95% confidence interval, was calculated. For antagonist assays, the relative inhibitory potency of transactivation activity of the test compound with respect to the standard antagonist, ICI 164,384 was calculated. For compounds showing significant agonist or antagonist activity in these initial screens, more accurate EC₅₀ values were determined by generating twelve-point curves with 3-fold dilutions of the compounds. In this case, the range of concentrations was selected based on the compound activity in the initial screens.

The following compounds of the invention were determined to be active (i.e., have agonist or antagonist values of EC₅₀≦4×10⁻⁶ M (ERα) and/or EC₅₀≦4×10⁻⁶ M (ERβ)) against either or both ERα and ERβ: 4-{5-[2-(4-hydroxyphenyl)ethyl]-4-benzylisoxazol-3-yl}phenol, 4-[4-ethyl-5-(phenoxymethyl)isoxazol-3-yl]phenol, 4-[5-(4-hydroxyphenyl)-4-phenylisoxazol-3-yl]phenol, 4-[4-ethyl-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol, 4-{5-[2-(4-hydroxyphenyl)ethyl]-4-phenylisoxazol-3-yl}phenol, 4-[5-(4-hydroxyphenyl)-4-benzylisoxazol-3-yl]phenol, 4-[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]phenol, 4-[5-(4-hydroxyphenyl)isoxazol-3-yl]phenol, 4-{5-(4-hydroxyphenyl)-4-[4-(2-piperidylethoxy)phenyl]isoxazol-3-yl}phenol, 4-{4-(4-hydroxyphenyl)-3-[4-2-piperidylethoxy)phenyl]isoxazol-5-yl}phenol, 3-[4,5-bis(4-hydroxyphenyl)isoxazol-3-yl]phenol, 2-[4,5-bis (4-hydroxyphenyl)isoxazol-3-yl]phenol, 4-[3-(4-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol, 4-[3-(4-hydroxyphenyl)-5-phenylisoxazol-4-yl]phenol, 4-[5-(4-fluorophenyl)-3-(4-hydroxyphenyl)isoxazol-4-yl]phenol, 4-{4-(4-hydroxyphenyl)-5-[3-(trifluoromethoxy)phenyl]isoxazol-3-yl}phenol, 4-{4-(4-hydroxyphenyl)-5-[4-(trifluoromethoxy)phenyl]isoxazol-3-yl}phenol, 4-[5-(4-hydroxyphenyl)-4-(phenoxymethyl)isoxazol-3-yl]phenol, 4-[5-4-hydroxyphenyl)-4-(phenylthiomethyl)isoxazol-3-yl]phenol, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone, 5-(4-hydroxyphenyl)-3-(4-methoxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(hydroxypiperidyl)ethoxy]phenyl ketone, 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl 4-[2-(hydroxypiperidyl)ethoxy]phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-hydroxyphenyl ketone, 4-hydroxyphenyl 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl ketone, 4-[4-bromo-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol, 4-[4-(bromomethyl)-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol, 4-{5-(4-hydroxyphenyl)-4-[(4-hydroxyphenoxy)methyl]isoxazol-3-yl}phenol, 4-[4-(hydroxymethyl)-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol, 4-(7-methoxy-4,5-dihydronaphtho[1,2-c]isoxazol-3-yl)phenol, 3-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol, 3-[3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 3-(4-hydroxyphenyl)naphtho[1,2-c]isoxazol-7-ol, 3-(3-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol, 3-(2-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-7-ol, 3-[5-(3-hydroxyphenyl)isoxazol-3-yl]phenol, 2-[3-(3-hydroxyphenyl)isoxazol-5-yl]phenol, 2-[5-(2-hydroxyphenyl)isoxazol-3-yl]phenol, 3-[3-(3-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol, 2-[3-(3-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol, 2-[3-(2-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol, 3-[4-ethyl-3-(3-hydroxyphenyl)isoxazol-5-yl]phenol, 2-[4-ethyl-3-(3-hydroxyphenyl)isoxazol-5-yl]phenol, 2-[4-ethyl-3-(2-hydroxyphenyl)isoxazol-5-yl]phenol, 3-[4-(4-hydroxyphenyl)-5-(3-hydroxyphenyl)isoxazol-3-yl]phenol, 2-[3-(3-hydroxyphenyl)-4-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 2-[4-(4-hydroxyphenyl)-5-(2-hydroxyphenyl)isoxazol-3-yl]phenol, 3-(2-hydroxyphenyl)-4,5-dihydronaphtho[2,1-d]isoxazol-7-ol, 2-(7-methoxy-4,5-dihydronaphtho[1,2-c]isoxazol-3-yl)phenol, 2-[5-(3-hydroxyphenyl)-4-methylisoxazol-3-yl]phenol, 2-[4-ethyl-5-(3-hydroxyphenyl)isoxazol-3-yl]phenol, 2-[4-(4-hydroxyphenyl)-5-(3-hydroxyphenyl)isoxazol-3-yl]phenol, 3-(5-(3-hydroxyphenyl)-4-{[4-(2-piperidylethoxy)phenyl]methyl}isoxazol-3-yl)phenol, 2-[3-(4-hydroxyphenyl)-4-phenylisoxazol-5-yl]phenol, 3-[3-(4-hydroxyphenyl)-4-phenylisoxazol-5-yl]phenol, 2-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 3-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 2-[3-(4-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol, 3-[3-(4-hydroxyphenyl)-4-methylisoxazol-5-yl]phenol, 2-[3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 4-(5-(4-hydroxyphenyl)-4-{[4-(2-piperidylethoxy)phenyl]methyl}isoxazol-3-yl)phenol, 2-[5-(4-hydroxyphenyl)-4-methylisoxazol-3-yl]phenol, 1-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-d]isoxazol-8-ol, 3-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-8-ol, 3-(4-hydroxyphenyl)-4,5-dihydronaphtho[1,2-c]isoxazol-6-ol, 4-[5-(4-hydroxyphenyl)-4-iodoisoxazol-3-yl]phenol, 4-[4-chloro-5-(4-hydroxyphenyl)isoxazol-3-yl]phenol, 3-(4-hydroxyphenyl)naphtho[1,2-c]isoxazol-8-ol, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-benzylcarboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N,N-dibutylcarboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-[3-(2-oxopyrrolidinyl)propyl]carboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-(2-phenylethyl)carboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-[(4-hydroxyphenyl)methyl]carboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-(3-pyridylmethyl)carboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-(2-pyridylmethyl)carboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N,N-dimethylcarboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-ethylcarboxamide, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-pyrrolidinylethoxy)phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-morpholin-4-ylethoxy)phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol4-yl 4-[3-(dimethylamino)propoxy]phenyl ketone, 4-[3-(diethylamino)propoxy]phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-cyclopropylcarboxamide, [3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]-N-cyclobutylcarboxamide, 4-[2-(diethylamino)ethoxy]phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(dimethylamino)ethoxy]phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-{2-[methylbenzylamino]ethoxy}phenyl ketone, 2-(4-{[3,5-bis(4-hydroxyphenyl)isoxazol-4-yl]carbonyl}phenoxy)-N,N-dimethylacetamide, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[2-(1-methylpyrrolidin-2-yl)ethoxy]phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[(1-methyl(3-piperidyl))methoxy]phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-[3-(4-methylpiperazinyl)propoxy]phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(1-methyl(4-piperidyloxy))phenyl ketone, 3-ethyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-methylphenol, 3-bromo-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 3-butyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-hexylphenol, 3-(2-bromopropyl)-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 3,5-bis(4-hydroxyphenyl)isoxazole-4-carbaldehyde, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-iodophenol, 3-chloro-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-fluorophenol, 2-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-5-hydroxybenzoic acid, ethyl 2-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-5-hydroxybenzoate, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-(methylsulfinyl)phenol, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-sulfanylphenol, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-methylphenol, 2-butyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5yl]phenol, 2-ethyl-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 2-bromo4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, 4-[3-(4-butanoyloxyphenyl)-4-ethylisoxazol-5-yl]phenyl butanoate, 4-[3-(4-acetyloxyphenyl)-4-ethylisoxazol-5-yl]phenyl acetate, 3-(4-butanoyloxyphenyl)naphtho[1,2-c]isoxazol-7-yl butanoate, 3-(4-acetyloxyphenyl)naphtho[1,2-c]isoxazol-7-yl acetate, 3,5-bis(4-methoxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone, chloride, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-hexylphenol, 2-chloro-4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]phenol, ethyl 5-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-hydroxybenzoate, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-methylphenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 2-chlorophenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-chlorophenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-chlorophenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 2-fluorophenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-nitrophenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-nitrophenyl ketone, 3,4-dichlorophenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-butylphenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(tert-butyl)phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-hydroxyphenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 2-hydroxyphenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl phenyl ketone, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-methoxyphenyl ketone, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-phenylthiophenol, 5-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-hydroxybenzamide, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-phenylthiophenol, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-methylthiophenol, 4-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-3-phenylphenol, {4-[4-ethyl-3(4-hydroxyphenyl)isoxazol-5-yl]phenyl}(methylsulfonyl)amine, 5-[4-ethyl-3-(4-hydroxyphenyl)isoxazol-5-yl]-2-methoxybenzamide, 5-[4-ethyl-3-(4-methoxyphenyl)isoxazol-5-yl]-2-hydroxybenzamide, 2-[4-ethyl-3-(4-methoxyphenyl)isoxazol-5-yl]-5-hydroxybenzamide, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-(2-piperidylethoxy)phenyl ketone, chloride, 5-(4-hydroxyphenyl)-3-(4-methoxyphenyl)isoxazol-4-yl 3-(2-piperidylethoxy)phenyl ketone, chloride, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-(2-pyrrolidinylethoxy)phenyl ketone, chloride, 3-[2-(diethylamino)ethoxy]phenyl 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl ketone, chloride, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-[(1-methyl(3-piperidyl))methoxy]phenyl ketone, chloride, 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 3-[2-(dimethylamino)ethoxy]phenyl ketone, chloride, 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl 3-[(1-methyl(3-piperidyl))methoxy]phenyl ketone, chloride, 3-[2-(dimethylamino)ethoxy]phenyl 3-(4-hydroxyphenyl)-5-(4-methoxyphenyl)isoxazol-4-yl ketone, chloride, 4-[4-ethyl-3-(4-hydroxy-2-methylphenyl)isoxazol-5-yl]-3-methylphenol, 4-[3-(4-hydroxyphenyl)-4-propylisoxazol-5-yl]phenol, and 4-[3-(4-hydroxyphenyl)-4-prop-2-enylisoxazol-5-yl]phenol.

5.2.2.4 MCF-7 Cell Proliferation Assays

This assay determines the estrogen agonist/antagonist activity of a test compound by the effect of the test compound on the proliferation of MCF-7 cells as measured by the incorporation of 5-bromo-2′-deoxyuridine (“BrdU”) in a chemiluminescent assay format.

MCF-7 cells (ATCC HTB-22) were maintained in log-phase culture using DMEM/HamF12 medium (v/v 1/1) that had been supplemented with 10% fetal bovine serum (“FBS”), at 37° C., and under at 5% CO₂ atmosphere. The cells were plated in a 96-well plate at a density of 7,000 cells per well. After 24 hours, the cells were further incubated in phenol red-free DMEM/HamF12 medium supplemented with 10% FBS that had been filtered with dextran-coated charcoal to deplete endogenous estrogen (DCC-FBS). The cells were incubated in this medium for an additional 24 hours, at which time either test compound at varying concentrations to determine the IC₅₀ for the compound. Each test compound was incubated with the cells either in the absence of estradiol (detection of estrogen agonist activity) or in the presence of 1 nM estradiol (detection of estrogen antagonist activity).

The cells were cultured in the presence of test compounds for 24 hours at 37° C. and under a 5% CO₂ atmosphere. Cell proliferation was detected by measuring the level of BrdU incorporation into DNA. This was accomplished using a commercially available reagent kit (Boeringer Mannheim/Roche). The assay was run according to the manufacturers direction. Ten microliters of BrDU labeling reagent, diluted according to the manufacturers directions, was added directly into each well, and incubation was continued for four hours. The culture media was then aspirated from the wells, and 100 μl of the fixing/denaturing agent from the kit was added. The cells were fixed for 30 minutes at room temperature. The plates were aspirated again, and 100 μl of peroxidase-labeled anti-BrdU antibody from the kit was added to each well. After one hour, the plates were washed six times with phosphate buffered saline (“PBS”), and 100 μl of SUPERSIGNAL (a chemilumiscent peroxidase substrate, Pierce Chemical) was added. The plates were shaken for ten minutes at room temperature, and the resulting chemiluminescent signals were counted using a TRILUX scintillation counter. Two compounds of the invention, 4-{5-(4-hydroxyphenyl)4-[4-(2-piperidylethoxy)phenyl]isoxazol-3-yl}phenol and 3,5-bis(4-hydroxyphenyl)isoxazol-4-yl 4-(2-piperidylethoxy)phenyl ketone, were tested using the above-described protocol, were determined to have IC₅₀ values of less than 600 nM in the presence of 1 nM estradiol.

Thus, the present invention will be seen to provide new compounds that have strong estrogen receptor-modulating action. These compounds can be employed in compositions and methods for treating estrogen receptor-mediated disorders, such as osteoporosis, breast and endometrial cancer, Alzheimer's disease, and atherosclerosis.

The disclosure above is for the purposes of illustration and not limitation. Those having skill in the arts relevant to the present invention (e.g., the organic chemistry, medicinal chemistry, endocrinology, and medical arts) will appreciate from the foregoing the present invention encompasses many additional embodiments of the invention that are not described explicitly, but which nevertheless are provided by the teachings of the present invention. Such additional embodiments include, but are not limited to, estrogen receptor-mediated diseases other than osteoporosis, breast and endometrial cancer, Alzheimer's disease, and atherosclerosis, that are preventable or treatable using the compounds, compositions, and methods of the invention. Still other aspects include compounds that can be designed, synthesized, and tested for therapeutic or prophylactic effect using the teachings of the foregoing disclosure.

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What is claimed:
 1. A compound having the formula:

and its pharmaceutically acceptable salts, wherein: X₁ and X₂ are selected independently from the group consisting of nitrogen and oxygen such that if one of X₁ and X₂ is nitrogen, then the other of X₁ and X₂ is oxygen to form thereby an isoxazole ring structure; R₁ and R₃ are selected independently from the group consisting of optionally substituted loweralkyl, aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, aralkyl, heteroaralkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl; and R₂ is selected from the group consisting of hydrogen, halo, cyano, nitro, thio, amino, carboxyl, formyl, and optionally substituted loweralkyl, loweralkylcarbonyloxy, arylcarbonyloxy, heteroarylcarbonyloxy, cycloalkylcarbonyloxy, cycloheteroalkylcarbonyloxy, aralkycarbonyloxy, heteroaralkylcarbonyloxy, (cycloalkyl)alkylcarbonyloxy, (cycloheteroalkyl)alkylcarbonyloxy, loweralkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, cycloalkylcarbonyl, cycloheteroalkylcarbonyl, aralkycarbonyl, heteroaralkylcarbonyl, (cycloalkyl)alkylcarbonyl, (cycloheteroalkyl)alkylcarbonyl, loweralkylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, cycloalkylaminocarbonyl, (cycloalkyl)alkylaminocarbonyl, cycloheteroalkylaminocarbonyl, (cycloheteroalkyl)alkylaminocarbonyl, loweralkylcarbonylamino, arylcarbonylamino, heteroarylcarbonylamino, cycloalkylcarbonylamino, cycloheteroalkylcarbonylamino, aralkylcarbonylamino, heteroaralkylcarbonylamino, (cycloalkyl)alkylcarbonylamino, (cycloheteroalkyl)alkylcarbonylamino, loweralkylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino, loweralkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, cycloalkylsulfonyl, cycloheteroalkylsulfonyl, aralkylsulfonyl, heteroaralkylsulfonyl, (cycloalkyl)alkylsulfonyl, (cycloheteroalkyl)alkylsulfonyl, loweralkylsulfinyl, arylsulfinyl, heteroarylsulfinyl, cycloalkylsulfinyl, cycloheteroalkylsulfinyl, aralkylsulfinyl, heteroaralkylsulfinyl, (cycloalkyl)alkylsulfinyl, (cycloheteroalkyl)alkylsulfinyl, loweralkyloxy, aryloxy, heteroaryloxy, cycloalkyloxy, cycloheteroalkyloxy, aralkyloxy, heteroaralkyloxy, (cycloalkyl)alkyloxy, and (cycloheteroalkyl)alkyloxy, loweralkylthio, arylthio, heteroarylthio, cycloalkylthio, cycloheteroalkylthio, aralkylthio, heteroaralkylthio, (cycloalkyl)alkylthio, (cycloheteroalkyl)alkylthio, loweralkylthiocarbonyl, arylthiocarbonyl, heteroarylthiocarbonyl, cycloalkylthiocarbonyl, cycloheteroalkylthiocarbonyl, aralkythiocarbonyloxythiocarbonyl, heteroaralkylthiocarbonyl, (cycloalkyl)alkylthiocarbonyl, (cycloheteroalkyl)alkylthiocarbonyl, heteroarylcarbonylthio, cycloalkylcarbonylthio, cycloheteroalkylcarbonylthio, aralkycarbonylthiooxycarbonylthio, heteroaralkylcarbonylthio, (cycloalkyl)alkylcarbonylthio, (cycloheteroalkyl)alkylcarbonylthio, loweralkyloxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, cycloalkyloxycarbonyl, cycloheteroalkyloxycarbonyl, aralkyoxycarbonyl, heteroaralkyloxycarbonyl, (cycloalkyl)alkyloxycarbonyl, (cycloheteroalkyl)alkyloxycarbonyl, iminoloweralkyl, iminocycloalkyl, iminocycloheteroalkyl, iminoaralkyl, iminoheteroaralkyl, (cycloalkyl)iminoalkyl, (cycloheteroalkyl)iminoalkyl, (cycloiminoalkyl)alkyl, (cycloiminoheteroalkyl)alkyl, oximinoloweralkyl, oximinocycloalkyl, oximinocycloheteroalkyl, oximinoaralkyl, oximinoheteroaralkyl, (cycloalkyl)oximinoalkyl, (cyclooximinoalkyl)alkyl, (cyclooximinoheteroalkyl)alkyl, and (cycloheteroalkyl)oximinoalkyl; provided that when R₂ is hydrogen, X₁ is nitrogen, and X₂ is oxygen, then: R₁ cannot be phenyl substituted with one or two trifluoromethyl groups when R₃ is 2-carboxyphenyl or 2-(alkyloxycarbonyl)phenyl; and R₁ cannot be 2-(alkylaminocarbonyl)phenyl, 2-bromomethylphenyl, 2-chloromethylphenyl, 2-(hydroxymethyl)phenyl, 2-carboxyphenyl, 2-(bromocarbonyl)phenyl, 2-(chlorocarbonyl)phenyl, or 2-(alkylcarbonyloxymethyl)phenyl, when R₃ is phenyl or phenyl substituted with alkyl, chloro, fluoro, or trifluoromethyl individually.
 2. The compound of claim 1, wherein R₁ and R₃ are selected independently from the group consisting of optionally substituted cycloalkyl, cycloheteroalkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl.
 3. The compound of claim 1, wherein R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl.
 4. The compound of claim 3, wherein R₁ and R₃ are selected independently from the group consisting of optionally substituted heteroaryl and heteroaralkyl.
 5. The compound of claim 3, wherein R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl.
 6. The compound of claim 5, wherein at least one of R₁ and R₃ is substituted with at least one hydroxyl, alkyloxy, aryloxy, thio, alkylthio, or arylthio group.
 7. The compound of claim 6, wherein at least one of R₁ and R₃ is selected independently from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl.
 8. The compound of claim 7, wherein at least one of R₁ and R₃ is substituted optionally with a substituent selected from the group consisting of halogen, nitro, cyano, loweralkyl, halolowerlalkyl, loweralkyloxy, haloloweralkyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, alkylsulfonylamino, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, lowerakylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, and heteroaralkylaminocarbonyl.
 9. The compound of claim 8, wherein at least one of R₁ and R₃ is further substituted optionally with a substituent selected from the group consisting of halogen, nitro, cyano, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkylthio, aminocarbonyl, and loweralkylsulfinyl.
 10. The compound of claim 1, wherein R₂ is selected from the group consisting of hydrogen, halo, and optionally substituted loweralkyl, haloloweralkyl, aryl, aralkyl, heteroaryl, heteroaralkyl, aryloxyalkyl, arylthioalkyl, arylcarbonyl, heteroarylcarbonyl, loweralkylcarbonyl, aminocarbonyl, arylaminocarbonyl, loweralkylaminocarbonyl, aralkylaminocarbonyl, (heterocycloloweralkyl)alkylaminocarbonyl, heteroarylaminocarbonyl, heteroaralkylaminocarbonyl, (cycloloweralkyl)aminocarbonyl, formyl, amino, loweralkylamino, and alkenyl.
 11. The compound of claim 10, wherein R₂ is selected from the group consisting of hydrogen and halo.
 12. The compound of claim 10, wherein R₂ is selected from the group consisting of optionally substituted phenyl, phenylloweralkyl, hydroxyphenyl, loweralkyloxyphenyl, haloloweralkylsulfonylloweralkyloxyphenyl, diloweralkylaminoloweralkyloxyphenyl, (cycloaminoloweralkyl)loweralkyloxyphenyl, and (heterocycloalkyl)loweralkyloxyphenyl.
 13. The compound of claim 10, wherein R₂ is selected from the group consisting of optionally substituted loweralkyl, haloloweralkyl, hydroxyalkyl, phenyloxyloweralkyl, hydroxyphenyloweralkyl, haloloweralkylsulfonylloweralkyl, and phenylthioloweralkyl.
 14. The compound of claim 10, wherein R₂ is selected from the group consisting of optionally substituted phenylcarbonyl, (heterocycloalkyl)loweralkyloxyphenylcarbonyl, hydroxyphenylcarbonyl, halophenylcarbonyl, phenylloweralkylaminocarbonyl, diloweralkylaminocarbonyl, phenylloweralkylaminocarbonyl, hydroxyphenyllowerlakylaminocarbonyl, cycloalkylaminocarbonyl, loweralkylphenylcarbonyl, haloloweralkylsulfonylloweralkyloxyphenylcarbonyl, and nitrophenylcarbonyl.
 15. The compound of claim 14, wherein R₁ and R₃ are selected independently from the group consisting of optionally substituted cycloalkyl, cycloheteroalkyl, (cycloalkyl)alkyl, and (cycloheteroalkyl)alkyl.
 16. The compound of claim 14, wherein R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl, heteroaryl, aralkyl, and heteroaralkyl.
 17. The compound of claim 16, wherein R₁ and R₃ are selected independently from the group consisting of optionally substituted aryl and aralkyl.
 18. The compound of claim 17, wherein at least one of R₁ and R₃ is substituted with at least one hydroxyl or thio group.
 19. The compound of claim 18, wherein at least one of R₁ and R₃ is selected independently from the group consisting of phenyl, phenyloxyloweralkyl, and phenylloweralkyl.
 20. The compound of claim 19, wherein at least one of R₁ and R₃ is substituted optionally with a substituent selected from the group consisting of halogen, loweralkyl, halolowerlalkyl, loweralkyloxy, halolowerlakyloxy, carboxy, loweralkyloxycarbonyl, aryloxycarbonyl, (cycloloweralkyl)oxycarbonyl, aralkyloxycarbonyl, heteroaryloxycarbonyl, heteroaralkyloxycarbonyl, (heterocycloloweralkyl)oxycarbonyl, loweralkylsulfinyl, loweralkylsulfonyl, loweralkylthio, arylthio, loweralkylcarbonyloxy, arylcarbonyloxy, aralkylcarbonyloxy, heteroarylcarbonyloxy, heteroaralkylcarbonyloxy, (cycloloweralkyl)carbonyloxy, (heterocycloloweralkyl)carbonyloxy, aminocarbonyl, loweraklylaminocarbonyl, arylaminocarbonyl, aralkylaminocarbonyl, heteroarylaminocarbonyl, and heteroaralkylaminocarbonyl.
 21. A composition for use in treating an estrogen receptor-mediated disorder in a mammal, comprising a therapeutically effective amount of a compound of claim 1 in a pharmaceutically effective carrier.
 22. A method for treating an estrogen receptor-mediated disorder in a mammal, comprising administering to such mammal a therapeutically effective amount of a compound of claim 1 in a pharmaceutically effective carrier.
 23. The method of claim 22, wherein said disease is chosen from the group consisting of: osteoporosis, estrogen-dependent cancer, Alzheimer's disease, and estrogen-dependent illness.
 24. A method for preventing an estrogen receptor-mediated disorder in a mammal, comprising administering to such mammal a prophylactically effective amount of a compound of claim 1 in a pharmaceutically effective carrier.
 25. The method of claim 24, wherein said disease is chosen from the group consisting of: osteoporosis, estrogen-dependent cancer, Alzheimer's disease and estrogen-dependent illness.
 26. A method for modulating the biological activity of an estrogen receptor, comprising exposing said estrogen receptor to a compound of claim 1 to modulate thereby the binding of said estrogen receptor to an associated estrogen receptor element.
 27. The method of claim 26, wherein said estrogen receptor is the α isoform.
 28. The method of claim 26, wherein said estrogen receptor is the β isoform. 